WO2024110786A1 - Revêtements barrières appliqués sur du papier et du carton revêtus de nanocellulose - Google Patents

Revêtements barrières appliqués sur du papier et du carton revêtus de nanocellulose Download PDF

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Publication number
WO2024110786A1
WO2024110786A1 PCT/IB2023/000723 IB2023000723W WO2024110786A1 WO 2024110786 A1 WO2024110786 A1 WO 2024110786A1 IB 2023000723 W IB2023000723 W IB 2023000723W WO 2024110786 A1 WO2024110786 A1 WO 2024110786A1
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WIPO (PCT)
Prior art keywords
nanocellulose
containing composition
composition comprises
base sheet
pulp
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PCT/IB2023/000723
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English (en)
Inventor
Thomas REEVE-LARSON
Mark Paradis
Jonathan Phipps
Per Svending
Daniel INGLE
David Skuse
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Fiberlean Technologies Limited
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Publication of WO2024110786A1 publication Critical patent/WO2024110786A1/fr

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    • D—TEXTILES; PAPER
    • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
    • D21H—PULP COMPOSITIONS; PREPARATION THEREOF NOT COVERED BY SUBCLASSES D21C OR D21D; IMPREGNATING OR COATING OF PAPER; TREATMENT OF FINISHED PAPER NOT COVERED BY CLASS B31 OR SUBCLASS D21G; PAPER NOT OTHERWISE PROVIDED FOR
    • D21H11/00—Pulp or paper, comprising cellulose or lignocellulose fibres of natural origin only
    • D21H11/16—Pulp or paper, comprising cellulose or lignocellulose fibres of natural origin only modified by a particular after-treatment
    • D21H11/18—Highly hydrated, swollen or fibrillatable fibres
    • D—TEXTILES; PAPER
    • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
    • D21H—PULP COMPOSITIONS; PREPARATION THEREOF NOT COVERED BY SUBCLASSES D21C OR D21D; IMPREGNATING OR COATING OF PAPER; TREATMENT OF FINISHED PAPER NOT COVERED BY CLASS B31 OR SUBCLASS D21G; PAPER NOT OTHERWISE PROVIDED FOR
    • D21H27/00—Special paper not otherwise provided for, e.g. made by multi-step processes
    • D21H27/30—Multi-ply
    • D21H27/38—Multi-ply at least one of the sheets having a fibrous composition differing from that of other sheets
    • D—TEXTILES; PAPER
    • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
    • D21F—PAPER-MAKING MACHINES; METHODS OF PRODUCING PAPER THEREON
    • D21F1/00—Wet end of machines for making continuous webs of paper
    • D21F1/02—Head boxes of Fourdrinier machines
    • D21F1/028—Details of the nozzle section
    • D—TEXTILES; PAPER
    • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
    • D21F—PAPER-MAKING MACHINES; METHODS OF PRODUCING PAPER THEREON
    • D21F9/00—Complete machines for making continuous webs of paper
    • D21F9/003—Complete machines for making continuous webs of paper of the twin-wire type
    • D21F9/006—Complete machines for making continuous webs of paper of the twin-wire type paper or board consisting of two or more layers
    • D—TEXTILES; PAPER
    • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
    • D21H—PULP COMPOSITIONS; PREPARATION THEREOF NOT COVERED BY SUBCLASSES D21C OR D21D; IMPREGNATING OR COATING OF PAPER; TREATMENT OF FINISHED PAPER NOT COVERED BY CLASS B31 OR SUBCLASS D21G; PAPER NOT OTHERWISE PROVIDED FOR
    • D21H11/00—Pulp or paper, comprising cellulose or lignocellulose fibres of natural origin only
    • D21H11/02—Chemical or chemomechanical or chemothermomechanical pulp
    • D21H11/04—Kraft or sulfate pulp
    • D—TEXTILES; PAPER
    • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
    • D21H—PULP COMPOSITIONS; PREPARATION THEREOF NOT COVERED BY SUBCLASSES D21C OR D21D; IMPREGNATING OR COATING OF PAPER; TREATMENT OF FINISHED PAPER NOT COVERED BY CLASS B31 OR SUBCLASS D21G; PAPER NOT OTHERWISE PROVIDED FOR
    • D21H17/00—Non-fibrous material added to the pulp, characterised by its constitution; Paper-impregnating material characterised by its constitution
    • D21H17/20—Macromolecular organic compounds
    • D21H17/21—Macromolecular organic compounds of natural origin; Derivatives thereof
    • D21H17/24—Polysaccharides
    • D21H17/28—Starch
    • D21H17/29—Starch cationic
    • D—TEXTILES; PAPER
    • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
    • D21H—PULP COMPOSITIONS; PREPARATION THEREOF NOT COVERED BY SUBCLASSES D21C OR D21D; IMPREGNATING OR COATING OF PAPER; TREATMENT OF FINISHED PAPER NOT COVERED BY CLASS B31 OR SUBCLASS D21G; PAPER NOT OTHERWISE PROVIDED FOR
    • D21H17/00—Non-fibrous material added to the pulp, characterised by its constitution; Paper-impregnating material characterised by its constitution
    • D21H17/20—Macromolecular organic compounds
    • D21H17/33—Synthetic macromolecular compounds
    • D21H17/34—Synthetic macromolecular compounds obtained by reactions only involving carbon-to-carbon unsaturated bonds
    • D21H17/36—Polyalkenyalcohols; Polyalkenylethers; Polyalkenylesters
    • D—TEXTILES; PAPER
    • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
    • D21H—PULP COMPOSITIONS; PREPARATION THEREOF NOT COVERED BY SUBCLASSES D21C OR D21D; IMPREGNATING OR COATING OF PAPER; TREATMENT OF FINISHED PAPER NOT COVERED BY CLASS B31 OR SUBCLASS D21G; PAPER NOT OTHERWISE PROVIDED FOR
    • D21H17/00—Non-fibrous material added to the pulp, characterised by its constitution; Paper-impregnating material characterised by its constitution
    • D21H17/20—Macromolecular organic compounds
    • D21H17/33—Synthetic macromolecular compounds
    • D21H17/34—Synthetic macromolecular compounds obtained by reactions only involving carbon-to-carbon unsaturated bonds
    • D21H17/37—Polymers of unsaturated acids or derivatives thereof, e.g. polyacrylates
    • D21H17/375—Poly(meth)acrylamide
    • D—TEXTILES; PAPER
    • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
    • D21H—PULP COMPOSITIONS; PREPARATION THEREOF NOT COVERED BY SUBCLASSES D21C OR D21D; IMPREGNATING OR COATING OF PAPER; TREATMENT OF FINISHED PAPER NOT COVERED BY CLASS B31 OR SUBCLASS D21G; PAPER NOT OTHERWISE PROVIDED FOR
    • D21H17/00—Non-fibrous material added to the pulp, characterised by its constitution; Paper-impregnating material characterised by its constitution
    • D21H17/63—Inorganic compounds
    • D21H17/67—Water-insoluble compounds, e.g. fillers, pigments
    • D21H17/675—Oxides, hydroxides or carbonates
    • D—TEXTILES; PAPER
    • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
    • D21H—PULP COMPOSITIONS; PREPARATION THEREOF NOT COVERED BY SUBCLASSES D21C OR D21D; IMPREGNATING OR COATING OF PAPER; TREATMENT OF FINISHED PAPER NOT COVERED BY CLASS B31 OR SUBCLASS D21G; PAPER NOT OTHERWISE PROVIDED FOR
    • D21H17/00—Non-fibrous material added to the pulp, characterised by its constitution; Paper-impregnating material characterised by its constitution
    • D21H17/71—Mixtures of material ; Pulp or paper comprising several different materials not incorporated by special processes
    • D21H17/74—Mixtures of material ; Pulp or paper comprising several different materials not incorporated by special processes of organic and inorganic material
    • D—TEXTILES; PAPER
    • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
    • D21H—PULP COMPOSITIONS; PREPARATION THEREOF NOT COVERED BY SUBCLASSES D21C OR D21D; IMPREGNATING OR COATING OF PAPER; TREATMENT OF FINISHED PAPER NOT COVERED BY CLASS B31 OR SUBCLASS D21G; PAPER NOT OTHERWISE PROVIDED FOR
    • D21H19/00—Coated paper; Coating material
    • D21H19/10—Coatings without pigments
    • D21H19/14—Coatings without pigments applied in a form other than the aqueous solution defined in group D21H19/12
    • D21H19/20—Coatings without pigments applied in a form other than the aqueous solution defined in group D21H19/12 comprising macromolecular compounds obtained by reactions only involving carbon-to-carbon unsaturated bonds
    • D—TEXTILES; PAPER
    • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
    • D21H—PULP COMPOSITIONS; PREPARATION THEREOF NOT COVERED BY SUBCLASSES D21C OR D21D; IMPREGNATING OR COATING OF PAPER; TREATMENT OF FINISHED PAPER NOT COVERED BY CLASS B31 OR SUBCLASS D21G; PAPER NOT OTHERWISE PROVIDED FOR
    • D21H19/00—Coated paper; Coating material
    • D21H19/10—Coatings without pigments
    • D21H19/14—Coatings without pigments applied in a form other than the aqueous solution defined in group D21H19/12
    • D21H19/20—Coatings without pigments applied in a form other than the aqueous solution defined in group D21H19/12 comprising macromolecular compounds obtained by reactions only involving carbon-to-carbon unsaturated bonds
    • D21H19/22—Polyalkenes, e.g. polystyrene
    • D—TEXTILES; PAPER
    • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
    • D21H—PULP COMPOSITIONS; PREPARATION THEREOF NOT COVERED BY SUBCLASSES D21C OR D21D; IMPREGNATING OR COATING OF PAPER; TREATMENT OF FINISHED PAPER NOT COVERED BY CLASS B31 OR SUBCLASS D21G; PAPER NOT OTHERWISE PROVIDED FOR
    • D21H19/00—Coated paper; Coating material
    • D21H19/10—Coatings without pigments
    • D21H19/14—Coatings without pigments applied in a form other than the aqueous solution defined in group D21H19/12
    • D21H19/34—Coatings without pigments applied in a form other than the aqueous solution defined in group D21H19/12 comprising cellulose or derivatives thereof
    • D—TEXTILES; PAPER
    • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
    • D21H—PULP COMPOSITIONS; PREPARATION THEREOF NOT COVERED BY SUBCLASSES D21C OR D21D; IMPREGNATING OR COATING OF PAPER; TREATMENT OF FINISHED PAPER NOT COVERED BY CLASS B31 OR SUBCLASS D21G; PAPER NOT OTHERWISE PROVIDED FOR
    • D21H19/00—Coated paper; Coating material
    • D21H19/80—Paper comprising more than one coating
    • D21H19/82—Paper comprising more than one coating superposed
    • D—TEXTILES; PAPER
    • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
    • D21H—PULP COMPOSITIONS; PREPARATION THEREOF NOT COVERED BY SUBCLASSES D21C OR D21D; IMPREGNATING OR COATING OF PAPER; TREATMENT OF FINISHED PAPER NOT COVERED BY CLASS B31 OR SUBCLASS D21G; PAPER NOT OTHERWISE PROVIDED FOR
    • D21H21/00—Non-fibrous material added to the pulp, characterised by its function, form or properties; Paper-impregnating or coating material, characterised by its function, form or properties
    • D21H21/14—Non-fibrous material added to the pulp, characterised by its function, form or properties; Paper-impregnating or coating material, characterised by its function, form or properties characterised by function or properties in or on the paper
    • D21H21/16—Sizing or water-repelling agents
    • D—TEXTILES; PAPER
    • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
    • D21H—PULP COMPOSITIONS; PREPARATION THEREOF NOT COVERED BY SUBCLASSES D21C OR D21D; IMPREGNATING OR COATING OF PAPER; TREATMENT OF FINISHED PAPER NOT COVERED BY CLASS B31 OR SUBCLASS D21G; PAPER NOT OTHERWISE PROVIDED FOR
    • D21H23/00—Processes or apparatus for adding material to the pulp or to the paper
    • D21H23/02—Processes or apparatus for adding material to the pulp or to the paper characterised by the manner in which substances are added
    • D21H23/22—Addition to the formed paper
    • D21H23/50—Spraying or projecting
    • D—TEXTILES; PAPER
    • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
    • D21H—PULP COMPOSITIONS; PREPARATION THEREOF NOT COVERED BY SUBCLASSES D21C OR D21D; IMPREGNATING OR COATING OF PAPER; TREATMENT OF FINISHED PAPER NOT COVERED BY CLASS B31 OR SUBCLASS D21G; PAPER NOT OTHERWISE PROVIDED FOR
    • D21H23/00—Processes or apparatus for adding material to the pulp or to the paper
    • D21H23/02—Processes or apparatus for adding material to the pulp or to the paper characterised by the manner in which substances are added
    • D21H23/22—Addition to the formed paper
    • D21H23/52—Addition to the formed paper by contacting paper with a device carrying the material
    • D21H23/64—Addition to the formed paper by contacting paper with a device carrying the material the material being non-fluent at the moment of transfer, e.g. in form of preformed, at least partially hardened coating
    • D—TEXTILES; PAPER
    • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
    • D21H—PULP COMPOSITIONS; PREPARATION THEREOF NOT COVERED BY SUBCLASSES D21C OR D21D; IMPREGNATING OR COATING OF PAPER; TREATMENT OF FINISHED PAPER NOT COVERED BY CLASS B31 OR SUBCLASS D21G; PAPER NOT OTHERWISE PROVIDED FOR
    • D21H27/00—Special paper not otherwise provided for, e.g. made by multi-step processes
    • D21H27/30—Multi-ply
    • D—TEXTILES; PAPER
    • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
    • D21J—FIBREBOARD; MANUFACTURE OF ARTICLES FROM CELLULOSIC FIBROUS SUSPENSIONS OR FROM PAPIER-MACHE
    • D21J1/00—Fibreboard
    • D21J1/08—Impregnated or coated fibreboard

Definitions

  • Nanocellulose e.g., microfibrillated cellulose (MFC) and nanofibrils
  • MFC microfibrillated cellulose
  • Nanocellulose has excellent end-of-life sustainability credentials in terms of recyclability, biodegradability, and compostability .
  • nanocellulose can improve many properties (e.g., strength, smoothness, and permeability, to name a few).
  • Nanocellulose can also provide beneficial barrier properties (e.g., related to oil and grease, oxygen, aromas, and mineral oils) when added to paper and packaging furnishes.
  • the present disclosure provides systems and methods for sequentially applying two or more nanocellulose-containing layers onto the surface of a paper or paperboard substrate (e.g., a wet consolidating base sheet web on a paper or paperboard machine).
  • a paper or paperboard substrate e.g., a wet consolidating base sheet web on a paper or paperboard machine.
  • Such sequential application may improve the barrier properties of the resulting paper or paperboard towards oil. grease, oxygen, aromas, and/or mineral oils.
  • the herein described sequential application of nanocellulose-containing layers may improve the strength of the resulting paper or paperboard, and serve as a smooth, low permeability surface for any subsequent coatings using conventional or not yet known surface application techniques at a later stage during the paper or paperboard making process, or using offline coaters, extruders, printing, or surface modification (e.g., chromatogeny) techniques.
  • nanocellulose-containing compositions which also optionally contain one or more inorganic particulate material (sometimes referred to as minerals )), can be applied to the surface of a dark base paper or paperboard substrate to provide optical coverage (i.e., white/light appearance) and a surface more suitable for printing.
  • the nanocellulose/inorganic particulate material -containing composition(s) may enable complete replacement of a white pulp layer in white top liner applications, with nanocellulose serving as the only binder (i.e., white pigmented layer).
  • each subsequent applicator may be positioned offset from the previous applicator, thereby ensuring sufficient overlap to achieve uniform coverage. Furthermore, the partial consolidation at each application point may lead to improved particle packing and, therefore, improved properties provided by the nanocellulose-containing composition layer.
  • Sequentially applying nanocellulose-containing compositions of different particle size, Fines B percentage and fibrillation properties enables successful dewatering when running at typical speeds used in paper/paperboard manufacturing. This is because dewatermg/drainage time is progressively increased as fibrillation is increased. Fines B percentage is increased and particle size is reduced.
  • a larger quantity of coarser (faster draining, lower quality) nanocellulose may be applied, and a smaller quantity of finer (slower draining, higher quality) nanocellulose may be applied in a subsequent step.
  • the coarser nanocellulose comprises a lower Fine B%, whereas the finer nanocellulose has higher Fines B%.
  • the net effect may be overall faster dewatering, improved performance, and lower nanocellulose costs. This may also be significant for particle packing in the layer of nanocellulose. This may also be significant for particle packing in the layer of nanocellulose.
  • applying the layers of nanocellulose in multiple steps may help to avoid defects, such as pinholes in nanocellulose barrier layers, as well as potentially improve strength (and coverage/printing quality in the context of inorganic particulate materialcontaining compositions).
  • the partial consolidation of each nanocellulose-containing layer, before the next nanocellulose-containing layer is applied, may help with particle packing and ensuring there are no breaks in the nanocellulose-containing layer.
  • Spraying is a technique that uses equipment that is inexpensive to fabricate.
  • Spray nozzles may be mounted on booms perpendicular to the paper machine direction and may be used in a modular fashion, allowing for easy adjustment of the separation between nozzles, the number of booms and the distance between them. This is beneficial for industrialization/scale-up.
  • the present disclosure also provides techniques for minimizing or otherwise avoiding surface defects, such as pinholes, of paper or paperboard produced using the herein described sequential application of one or more nanocellulose-containing compositions.
  • the abovedescribed sequential application of one or more nanocellulose-containing compositions, at the wet end of the paper machine, may be used to achieve a pre-coated/primed surface onto which a layer (or layers) of ethylene vinyl alcohol (EVOH), polyvinyl alcohol (PVOH), starch, and/or surface sizing agent may be applied.
  • EVOH ethylene vinyl alcohol
  • PVOH polyvinyl alcohol
  • starch polyvinyl alcohol
  • surface sizing agent may be applied.
  • the coat weight, of the EVOH, PVOH, starch, and/or surface sizing agent layer, required to achieve target barrier performance is significantly reduced when using the pre-coated/primed surface.
  • EVOH usually requires a precoated paper.
  • the teachings of the present disclosure enable EVOH and/or PVOH to be applied at the size press of a paper machine, rather than to a dried and pre-coated paper or paperboard.
  • starch applied at the size press can usually only meet a low-medium KIT rating at best.
  • the KIT rating may be improved.
  • wet end nanocellulose-containing composition(s) application and size press application of another material may serve as an effective means of achieving a defect- or near defect- free surface, which would serve as an effective surface for applying other coatings, such as water/moisture barriers.
  • another material e.g., EVOH, PVOH, starch, and/or surface sizing agent
  • a first aspect of the present disclosure relates to a method of manufacturing a multiply paper or paperboard product.
  • the method comprises providing a consolidating base sheet of pulp following a headbox of a paper or paperboard machine; applying two or more layers of one or more nanocellulose-containing compositions onto the consolidating base sheet to form a consolidating multi-layer paper or paperboard structured material; and at a size press section of the paper or paperboard machine, applying a layer to the top of the consolidating multi-layer paper or paperboard structured material, where the layer comprises at least one of ethylene vinyl alcohol (EVOH), polyvinyl alcohol (PVOH), starch, surface sizing agent microcrystalline cellulose, and nanocrystalline cellulose.
  • a first layer of nanocellulose-containing composition is applied to the consolidating base sheet in an amount ranging from about 0.
  • a second layer of nanocellulose- containing composition is applied to the consolidating base sheet in an amount ranging from about 1 g/m 2 to about 20 g/m 2 , and at least one of the first or second layers of nanocellulose- containing composition is applied by spraying.
  • the first nanocellulose-containing composition comprises first nanocellulose having a first Fines B% by fibre analyzer
  • the second nanocellulose- containing composition comprises second nanocellulose having a second Fines B% by fibre analyzer
  • the first Fines B% by fibre analyzer is lower than the second Fines B% by fibre analyzer.
  • the former is sometimes referred to a coarser nanocellulose (e g., MFC) and the latter is referred to as finer nanocellulose (e.g., MFC). Both relate to gradations in Fines B percentages.
  • the pulp comprises recycled pulp, papermill broke, paper streams rich in mineral fillers, cellulosic materials from a papermill, chemical pulp, thermomechanical pulp, chemi-thermomechanical pulp, mechanical pulp, or a combination thereof.
  • the pulp comprises recycled paperboard.
  • the recycled paperboard is recycled corrugated containers.
  • the nanocellulose comprises nanofibri Hated cellulose, microfibrillated cellulose, or a combination thereof.
  • the nanocellulose comprises microcrystalline cellulose, nanocrystalline cellulose, cellulose nanocrystals (CNCs), or a combination thereof.
  • the nanocellulose is produced from hardwood pulp, softwood pulp, wheat straw pulp, bamboo, bagasse, virgin fiber, chemical pulp, chemithermomechanical pulp, mechanical pulp, thermomechanical pulp, kraft pulp, bleached long fibre kraft pulp, eucalyptus pulp, spruce pulp, pine pulp, beech pulp, hemp pulp, acacia cotton pulp, recycled pulp, papermill broke, paper steam rich in mineral fillers, or a combination thereof.
  • the hardwood pulp is selected from the group consisting of eucalyptus, aspen, birch, and mixed hardwood pulps.
  • the softwood pulp is selected from the group consisting of spruce, pine, fir, larch, hemlock, and mixed softwood pulp.
  • the method further comprises applying one or more additional layers atop the two or more layers of one or more nanocellulose- containing compositions, where the one or more additional layers comprise one or more of a barrier layer, a wax layer, and a silicon layer.
  • the method further comprises applying an additional layer atop the two or more layers of one or more nanocellulose-containing compositions, where the additional layer consists essentially of inorganic particulate material and microfibrillated cellulose.
  • the inorganic particulate material comprises calcium carbonate, ground calcium carbonate, precipitated calcium carbonate, magnesium carbonate, dolomite, gypsum, an anhydrous kandite clay, kaolin, perlite, bentonite, diatomaceous earth, wollastonite, talc, magnesium hydroxide, titanium dioxide, or aluminium trihydrate, or a combination thereof.
  • the inorganic particulate material comprises ground calcium carbonate and precipitated calcium carbonate.
  • the two or more layers of the one or more nanocellulose-containing compositions are applied via spraying.
  • the first layer is applied using a slotted applicator, and the second layer is applied using spraying.
  • the slotted applicator is a slot coater.
  • the slotted applicator is a curtain coater.
  • applying the two or more layers of the one or more nanocellulose-containing compositions causes the consolidating multi-layer paper or paperboard structured material to have a heptane vapor transmission rate of about 0 g m' 2 day -1 to about 2,500 g m' 2 day' 1 .
  • applying the two or more layers of the one or more nanocellulose-containing compositions causes the consolidating multi-layer paper or paperboard structured material to have a heptane vapor transmission rate of about 0 g m -2 day' 1 to about 100 g m' 2 day' 1 .
  • applying the two or more layers of the one or more nanocellulose-containing compositions causes the consolidating multi-layer paper or paperboard structured material to have a heptane vapor transmission rate of about 100 g m' 2 day' 1 to about 2,500 g m' 2 day' 1 .
  • At least one of the two or more layers of the one or more nanocellulose-containing compositions is applied across substantially the entire width of the consolidating base sheet.
  • At least one of the two or more layers of the one or more nanocellulose-containing compositions is applied across the entire width of the consolidating base sheet.
  • the one or more nanocellulose-containing compositions comprises a first nanocellulose-containing composition; and the first nanocellulose-containing composition comprises nanofibrillated cellulose, microfibrillated cellulose, or a combination thereof.
  • the one or more nanocellulose-containing compositions comprises a first nanocellulose-containing composition; and the first nanocellulose-containing composition comprises microcrystalline cellulose, nanocrystalline cellulose, cellulose nanocrystals (CNCs), or a combination thereof.
  • the first nanocellulose containing composition comprises first nanocellulose in a range of about 0.5 wt% to about 6 wt% based on the total weight of the first nanocellulose-containing composition.
  • the first nanocellulose-containing composition comprises first nanocellulose in a range of about 1 wt% to about 2 wt% based on the total weight of the first nanocellulose-containing composition. [0046] In some embodiments of the first aspect, the first nanocellulose-containing composition comprises at least about 0.5 wt% first nanocellulose based on the total weight of the first nanocellulose-containing composition.
  • the first nanocellulose-containing composition comprises at least about 1 wt% first nanocellulose based on the total weight of the first nanocellulose-containing composition.
  • the first nanocellulose-containing composition comprises at most about 6 wt% first nanocellulose based on the total weight of the first nanocellulose-containing composition.
  • the first nanocellulose-containing composition comprises at most about 3 wt% first nanocellulose based on the total weight of the first nanocellulose-containing composition.
  • the first nanocellulose-containing composition comprises at most about 2 wt% first nanocellulose based on the total weight of the first nanocellulose-containing composition.
  • the first nanocellulose-containing composition comprises one or more inorganic particulate material.
  • the one or more inorganic particulate material comprises bentonite, alkaline earth metal carbonate, alkaline earth metal sulphate, dolomite, gypsum, hydrous kandite clay, anhydrous calcined kandite clay, talc, mica, perlite, diatomaceous earth, magnesium hydroxide, aluminum trihydrate, or a combination thereof.
  • the one or more inorganic particulate material is bentonite.
  • the first nanocellulose-containing composition comprises one or more starches.
  • the one or more starches are one or more cationic starches.
  • the first nanocellulose-containing composition comprises one or more sizing agents.
  • the one or more sizing agents comprise rosin, rosin/aluminum emulsion, cationic rosin emulsion, alk l ketene dimer, wax emulsion, succinic acid derivative, or a combination thereof.
  • the succinic acid derivative is alkenylsuccinic anhydride.
  • the first nanocellulose-containing composition comprises one or more polyacrylamides.
  • the one or more polyacrylamides comprise polydiallyldimethylammonium chloride (polyDADMAC).
  • the first nanocellulose-containing composition comprises one or more copolymers.
  • the one or more copolymers comprise ethylene vinyl alcohol (EV OH), polyvinyl alcohol (PVOH), or a combination thereof.
  • the one or more nanocellulose-containing compositions comprise a first nanocellulose containing composition and a second nanocellulose containing composition; and both the first nanocellulose-containing composition and the second nanocellulose containing composition are applied via spraying.
  • the one or more nanocellulose-containing compositions comprise a first nanocellulose containing composition and a second nanocellulose containing composition; the first nanocellulose-containing composition is applied using a slotted applicator; and the second nanocellulose-containing composition is applied using spraying.
  • the slotted applicator is a slot coater.
  • the slotted applicator is a curtain coater.
  • the first nanocellulose-containing composition has a first particle size distribution; the second nanocellulose-containing composition has a second particle size distribution; and the mean size, of the first particle size distribution, is greater than the mean size of the second particle size distribution.
  • the first nanocellulose-containing composition comprises first nanocellulose having a first Fines B% by fibre analyzer
  • the second nanocellulose-containing composition comprises second nanocellulose having a second Fines B% by fibre analyzer
  • the first Fines B% by fibre analyzer is lower than the second Fines B% by fibre analyzer.
  • the former is sometimes referred to a coarser nanocellulose (e.g., MFC) and the latter is referred to as finer nanocellulose (e.g., MFC). Both relate to gradations in Fines B percentages.
  • the mean size of the first nanocellulose is from 5 pm to 500 pm.
  • the mean size, of the second nanocellulose is from 5 pm to 500 pm.
  • applying the second nanocellulose- containing composition causes the consolidating base sheet to have a heptane vapor transmission rate of about 0 g m' 2 day 1 to about 2,500 g m' 2 day -1 .
  • applying the second nanocellulose- containing composition causes the consolidating base sheet to have a heptane vapor transmission rate of about 0 g m' 2 day' 1 to about 100 g m' 2 day' 1 .
  • applying the second nanocellulose- containing composition causes the consolidating base sheet to have a heptane vapor transmission rate of about 100 g m' 2 day' 1 to about 2,500 g m' 2 day' 1 .
  • At least one of the first nanocellulose- containing composition and the second nanocellulose-containing composition is applied across substantially the entire width of the consolidating base sheet.
  • At least one of the first nanocellulose- containing composition and the second nanocellulose-containing composition is applied across the entire width of the consolidating base sheet.
  • the second nanocellulose-containing composition comprises nanofibrillated cellulose, microfibrillated cellulose, or a combination thereof.
  • the second nanocellulose-containing composition comprises microcrystalline cellulose, nanocrystalline cellulose, cellulose nanocrystals (CNCs), or a combination thereof.
  • the second nanocellulose-containing composition comprises second nanocellulose in a range of about 0.5 wt% to about 6 wt% based on the total weight of the second nanocellulose-containing composition.
  • the second nanocellulose-containing composition comprises second nanocellulose in a range of about 1 wt% to about 2 wt% based on the total weight of the second nanocellulose-containing composition. [0080] In some embodiments of the first aspect, the second nanocellulose-containing composition comprises at least about 0.5 wt% second nanocellulose based on the total weight of the second nanocellulose-containing composition.
  • the second nanocellulose-containing composition comprises at least about 1 wt% second nanocellulose based on the total weight of the second nanocellulose-containing composition.
  • the second nanocellulose-containing composition comprises at most about 6 wt% second nanocellulose based on the total weight of the second nanocellulose-containing composition.
  • the second nanocellulose-containing composition comprises at most about 3 wt% second nanocellulose based on the total weight of the second nanocellulose-containing composition.
  • the second nanocellulose-containing composition comprises at most about 2 wt% second nanocellulose based on the total weight of the second nanocellulose-containing composition.
  • the second nanocellulose containing composition comprises one or more inorganic particulate material.
  • the first nanocellulose-containing composition comprises the one or more inorganic particulate material, and the second nanocellulose-containing composition is free of inorganic particulate material.
  • the one or more inorganic particulate material comprise bentonite, alkaline earth metal carbonate, alkaline earth metal sulphate, dolomite, gypsum, hydrous kandite clay, anhydrous calcined kandite clay, talc, mica, perlite, diatomaceous earth, magnesium hydroxide, aluminum trihydrate, or a combination thereof.
  • the one or more inorganic particulate material is bentonite.
  • the second nanocellulose containing composition comprises one or more starches.
  • the one or more starches comprise one or more cationic starches.
  • the second nanocellulose containing composition comprises one or more sizing agents.
  • the one or more sizing agents comprise rosin, rosin/aluminum emulsion, cationic rosin emulsion, alkylketene dimer, wax emulsion, succinic acid derivative, or a combination thereof.
  • the succinic acid derivative is alkenylsuccinic anhydride.
  • the second nanocellulose containing composition comprises one or more polyacrylamides.
  • the one or more polyacrylamides comprise poly diallyldimethylammonium chloride (polyDADMAC).
  • the second nanocellulose containing composition comprises one or more copolymers.
  • the one or more copolymers comprise ethylene vinyl alcohol (EVOH), polyvinyl alcohol (PVOH), or a combination thereof.
  • the surface sizing agent applied to the consolidating multi-layer paper or paperboard structured material at the size press section, comprises rosin, rosin/aluminum emulsion, cationic rosin emulsion, alkylketene dimer, wax emulsion, succinic acid derivative, or a combination thereof.
  • the surface sizing agent, applied to the consolidating multi-layer paper or paperboard structured material at the size press section is selected from the group consisting of rosin, rosin/aluminum emulsion, cationic rosin emulsion, alkylketene dimer, wax emulsion, and succinic acid derivative.
  • the succinic acid derivative is alkenylsuccinic anhydride.
  • the paper or paperboard comprises a base layer having a grammage ranging from about 25 g/m 2 to about 500 g/m 2 .
  • the paper or paperboard is a white top containerboard.
  • a third aspect of the present disclosure relates to a system for producing a paper or paperboard, where the system comprises a headbox configured to output a consolidating base sheet; means for sequentially applying two or more layers of a nanocellulose-containing composition onto the surface of the consolidating base sheet, wherein at least one of the two or more layers is sprayed onto the consolidating base sheet; and a size press section comprising means for applying a layer to the top of the consolidating base sheet, wherein the layer comprises at least one of ethylene vinyl alcohol (EVOH), polyvinyl alcohol (PVOH), starch, surface sizing agent, microcrystalline cellulose, and nanocrystalline cellulose.
  • EVOH ethylene vinyl alcohol
  • PVH polyvinyl alcohol
  • the first nanocellulose-containing composition comprises first nanocellulose having a first Fines B% by fibre analyzer
  • the second nanocellulose- containing composition comprises second nanocellulose having a second Fines B% by fibre analyzer
  • the first Fines B% by fibre analyzer is lower than the second Fines B% by fibre analyzer.
  • the former is sometimes referred to a coarser nanocellulose (e g., MFC) and the latter is referred to as finer nanocellulose (e.g., MFC). Both relate to gradations in Fines B percentages
  • the means for sequentially applying comprises a first spray boom configured to spray a first layer of the nanocellulose-containing composition, onto the surface of the consolidating base sheet; and a second spray boom configured to spray a second layer of the nanocellulose-containing composition, onto the surface of the consolidating base sheet.
  • the means for sequentially applying comprises a slotted applicator configured to apply a first layer of the nanocellulose- containing composition onto the surface of the consolidating base sheet; and a spray boom configured to spray a second layer of the nanocellulose-containing composition, onto the surface of the consolidating base sheet.
  • the slotted applicator is a slot coater.
  • the second layer causes the consolidating base sheet to have a heptane vapor transmission rate of about 0 g nr 2 day 1 to about 2,500 g m -2 day -1 .
  • the second layer causes the consolidating base sheet to have a heptane vapor transmission rate of about 0 g m' 2 day' 1 to about 100 g m' 2 day' 1 .
  • the second layer causes the consolidating base sheet to have a heptane vapor transmission rate of about 100 g m' 2 day' 1 to about 2,500 g m' 2 day' 1 .
  • At least one of the two or more layers is applied across substantially the entire width of the consolidating base sheet.
  • At least one of the two or more layers is applied across the entire width of the consolidating base sheet.
  • the nanocellulose-containing composition comprises nanofibrillated cellulose, microfibrillated cellulose, or a combination thereof.
  • the nanocellulose-containing composition comprises microcrystalline cellulose, nanocrystalline cellulose, cellulose nanocrystals (CNCs), or a combination thereof.
  • the nanocellulose-containing composition comprises nanocellulose in a range of about 0.5 wt% to about 6 wt% based on the total weight of the nanocellulose-containing composition.
  • the nanocellulose-containing composition comprises nanocellulose in a range of about 1 wt% to about 2 wt% based on the total weight of the nanocellulose-containing composition.
  • the nanocellulose-containing composition comprises at least about 0.5 wt% nanocellulose based on the total weight of the nanocellulose-containing composition.
  • the nanocellulose-containing composition comprises at least about 1 wt% nanocellulose based on the total weight of the nanocellulose- containing composition.
  • the nanocellulose-containing composition comprises at most about 6 wt% nanocellulose based on the total weight of the nanocellulose- containing composition. [0123] In some embodiments of the third aspect, the nanocellulose-containing composition comprises at most about 3 wt% nanocellulose based on the total weight of the nanocellulose- containing composition.
  • the nanocellulose-containing composition comprises at most about 2 wt% nanocellulose based on the total weight of the nanocellulose- containing composition.
  • the nanocellulose-containing composition comprises one or more inorganic particulate material.
  • the one or more inorganic particulate material comprises bentonite, alkaline earth metal carbonate, alkaline earth metal sulphate, dolomite, gypsum, hydrous kandite clay, anhydrous calcined kandite clay, talc, mica, perlite, diatomaceous earth, magnesium hydroxide, aluminum trihydrate, or a combination thereof.
  • the one or more inorganic particulate material is bentonite.
  • the nanocellulose-containing composition comprises one or more starches.
  • the one or more starches are one or more cationic starches.
  • the nanocellulose-containing composition comprises one or more sizing agents.
  • the one or more sizing agents comprise rosin, rosin/aluminum emulsion, cationic rosin emulsion, alk l ketene dimer, wax emulsion, succinic acid derivative, or a combination thereof.
  • the succinic acid derivative is alkenylsuccinic anhydride.
  • the nanocellulose-containing composition comprises one or more polyacrylamides.
  • the one or more polyacrylamides comprise poly diallyldimethylammonium chloride (polyDADMAC).
  • the nanocellulose-containing composition comprises one or more copolymers.
  • the one or more copolymers comprise ethylene vinyl alcohol (EVOH), polyvinyl alcohol (PVOH), or a combination thereof.
  • the starch, applied to the consolidating base sheet at the size press section comprises one or more cationic starches.
  • the surface sizing agent, applied to the consolidating base sheet at the size press section comprises rosin, rosin/aluminum emulsion, cationic rosin emulsion, alkylketene dimer, wax emulsion, succinic acid derivative, or a combination thereof.
  • the surface sizing agent, applied to the consolidating base sheet at the size press section is selected from the group consisting of rosin, rosin/aluminum emulsion, cationic rosin emulsion, alkylketene dimer, wax emulsion, and succinic acid derivative.
  • the succinic acid derivative is alkenylsuccinic anhydride.
  • a fourth aspect of the present disclosure relates to a system of producing a paper or paperboard, where the system comprises a headbox configured to output a consolidating base sheet; a first means for applying a first layer of a first nanocellulose-containing composition onto the surface of the consolidating base sheet; a second means for applying a second layer of a second nanocellulose-containing composition onto the surface of the consolidating base sheet; and a size press section comprising means for applying a layer to the top of the consolidating base sheet, wherein the layer comprises at least one of ethylene vinyl alcohol (EVOH), polyvinyl alcohol (PVOH), starch, surface sizing agent, microcrystalline cellulose, and nanocrystalline cellulose, wherein at least one of the first layer or the second layer is sprayed onto the consolidating base sheet.
  • EVOH ethylene vinyl alcohol
  • PVH polyvinyl alcohol
  • the first nanocellulose-containing composition comprises first nanocellulose having a first Fines B% by fibre analyzer
  • the second nanocellulose- containing composition comprises second nanocellulose having a second Fines B% by fibre analyzer
  • the first Fines B% by fibre analyzer is lower than the second Fines B% by fibre analyzer.
  • the former is sometimes referred to a coarser nanocellulose (e.g., MFC) and the latter is referred to as finer nanocellulose (e.g., MFC). Both relate to gradations in Fines B percentages.
  • the first means is a first spray boom configured to spray the first layer onto the surface of the consolidating base sheet
  • the second means is a second spray boom configured to spray the second layer onto the surface of the consolidating base sheet
  • the first means is a slotted applicator configured to apply the first layer onto the surface of the consolidating base sheet
  • the second means is a spray boom configured to spray the second layer onto the surface of the consolidating base sheet
  • the slotted applicator is a slot coater.
  • the slotted applicator is a curtain coater.
  • the first nanocellulose-containing composition has a first particle size distribution; the second nanocellulose-containing composition has a second particle size distribution; and the mean size, of the first particle size distribution, is greater than the mean size of the second particle size distribution.
  • the mean size first nanocellulose is from 5 pm to 500 pm.
  • the mean size of the second nanocellulose is from 5 pm to 500 pm.
  • the second nanocellulose-containing composition causes the consolidating base sheet to have a heptane vapor transmission rate of about 0 g nr 2 day' 1 to about 2,500 g m' 2 day' 1 .
  • the second nanocellulose-containing composition causes the consolidating base sheet to have a heptane vapor transmission rate of about 0 g nr 2 day' 1 to about 100 g m' 2 day' 1 .
  • the second nanocellulose-containing composition causes the consolidating base sheet to have a heptane vapor transmission rate of about 100 g m' 2 day' 1 to about 2,500 g m' 2 day' 1 .
  • At least one of the first nanocellulose- containing composition and the second nanocellulose-containing composition is applied across substantially the entire width of the consolidating base sheet.
  • at least one of the first nanocellulose- containing composition and the second nanocellulose-containing composition is applied across the entire width of the consolidating base sheet.
  • the first nanocellulose-containing composition comprises nanofibrillated cellulose, microfibrillated cellulose, or a combination thereof.
  • the first nanocellulose-containing composition comprises microcrystalline cellulose, nanocrystalline cellulose, cellulose nanocrystals (CNCs), or a combination thereof.
  • the first nanocellulose-containing composition comprises first nanocellulose in a range of about 0.5 wt% to about 6 wt% based on the total weight of the first nanocellulose-containing composition.
  • the first nanocellulose-containing composition comprises first nanocellulose in a range of about 1 wt% to about 2 wt% based on the total weight of the first nanocellulose-containing composition.
  • the first nanocellulose-containing composition comprises at least about 0.5 wt% first nanocellulose based on the total weight of the first nanocellulose-containing composition.
  • the first nanocellulose-containing composition comprises at least about 1 wt% first nanocellulose based on the total weight of the first nanocellulose-containing composition.
  • the first nanocellulose-containing composition comprises at most about 6 wt% first nanocellulose based on the total weight of the first nanocellulose-containing composition.
  • the first nanocellulose-containing composition comprises at most about 3 wt% first nanocellulose based on the total weight of the first nanocellulose-containing composition.
  • the first nanocellulose-containing composition comprises at most about 2 wt% first nanocellulose based on the total weight of the first nanocellulose-containing composition.
  • the second nanocellulose-containing composition comprises nanofibrillated cellulose, microfibrillated cellulose, or a combination thereof.
  • the second nanocellulose-containing composition comprises microcrystalline cellulose, nanocrystalline cellulose, cellulose nanocrystals (CNCs), or a combination thereof.
  • the second nanocellulose-containing composition comprises nanocellulose in a range of about 0.5 wt% to about 6 wt% based on the total weight of the second nanocellulose-containing composition.
  • the second nanocellulose-containing composition comprises second nanocellulose in a range of about 1 wt% to about 2 wt% based on the total weight of the second nanocellulose-containing composition.
  • the second nanocellulose-containing composition comprises at least about 0.5 wt% second nanocellulose based on the total weight of the second nanocellulose-containing composition.
  • the second nanocellulose-containing composition comprises at least about 1 wt% second nanocellulose based on the total weight of the second nanocellulose-containing composition.
  • the second nanocellulose-containing composition comprises at most about 6 wt% second nanocellulose based on the total weight of the second nanocellulose-containing composition.
  • the second nanocellulose-containing composition comprises at most about 3 wt% second nanocellulose based on the total weight of the second nanocellulose-containing composition.
  • the second nanocellulose-containing composition comprises at most about 2 wt% second nanocellulose based on the total weight of the second nanocellulose-containing composition.
  • At least one of the first nanocellulose- containing composition and the second nanocellulose containing composition comprises one or more inorganic particulate material.
  • the first nanocellulose-containing composition comprises the one or more inorganic particulate material, and the second nanocellulose-containing composition is free of inorganic particulate material.
  • the one or more inorganic particulate material comprises bentonite, alkaline earth metal carbonate, alkaline earth metal sulphate, dolomite, gypsum, hydrous kandite clay, anhydrous calcined kandite clay, talc, mica, perlite, diatomaceous earth, magnesium hydroxide, aluminum trihydrate, or a combination thereof.
  • the one or more inorganic particulate material is bentonite.
  • At least one of the first nanocellulose- containing composition and the second nanocellulose containing composition comprises one or more starches.
  • the one or more starches comprise one or more cationic starches.
  • At least one of the first nanocellulose- containing composition and the second nanocellulose containing composition comprises one or more sizing agents.
  • the one or more sizing agents comprise rosin, rosin/aluminum emulsion, cationic rosin emulsion, alkyl ketene dimer, wax emulsion, succinic acid derivative, or a combination thereof.
  • the succinic acid derivative is alkenylsuccinic anhydride.
  • At least one of the first nanocellulose- containing composition and the second nanocellulose containing composition comprises one or more polyacrylamides.
  • the one or more polyacrylamides comprise poly diallyldimethylammonium chloride (polyDADMAC).
  • At least one of the first nanocellulose- containing composition and the second nanocellulose containing composition comprises one or more copolymers.
  • the one or more copolymers comprise ethylene vinyl alcohol (EV OH), polyvinyl alcohol (PVOH), or a combination thereof.
  • the starch, applied to the consolidating base sheet at the size press section comprises one or more cationic starches.
  • the surface sizing agent, applied to the consolidating base sheet at the size press section comprises rosin, rosin/aluminum emulsion, cationic rosin emulsion, alkylketene dimer, wax emulsion, succinic acid derivative, or a combination thereof.
  • the surface sizing agent, applied to the consolidating base sheet at the size press section is selected from the group consisting of rosin, rosin/aluminum emulsion, cationic rosin emulsion, alkylketene dimer, wax emulsion, and succinic acid derivative.
  • the succinic acid derivative is alkenylsuccimc anhydride.
  • FIG. 1 is a top view of a paper or paperboard machine forming section equipped with surface applicator and spray booms capable of sequentially applying a single nanocellulose- containing composition.
  • Fig. 2 is a top view of a paper or paperboard machine forming section equipped with spray booms capable of sequentially applying a single nanocellulose-containing composition.
  • Fig. 3 is a top view of a paper or paperboard machine forming section equipped with surface applicator and spray booms capable of applying different nanocellulose-containing compositions.
  • Fig. 4 is a top view of a paper or paperboard machine forming section equipped with spray booms capable of applying different nanocellulose-containing compositions.
  • Fig. 5A is a photograph of an uncoated control of unbleached Kraft base paper surface.
  • Fig. 5B is a photograph of a spray coated (1 nozzle) unbleached Kraft paper surface at 2.5 g/m 2 MFC.
  • Fig. 5C is a photograph of a spray coated (2 nozzles) unbleached Kraft paper surface at 2.5 g/m 2 MFC
  • Fig. 5D is a photograph of a spray coated (3 nozzles) unbleached Kraft paper surface at 2.5 g/m 2 MFC.
  • Fig. 5E is a photograph of a spray coated (3 nozzles) unbleached Kraft paper surface at 2.25 g/m 2 MFC.
  • the spray coating composition for all samples was microfibrillated cellulose / ground calcium carbonate (1: 1) composition applied onto an unbleached Kraft base paper.
  • Fig. 6A is a photograph of an uncoated control of unbleached Kraft base paper surface.
  • Fig. 6B is a photograph of a spray coated (1 nozzle) unbleached Kraft paper surface at 2.5 g/m 2 MFC.
  • Fig. 6C is a photograph of a spray coated (2 nozzles) unbleached Kraft paper surface at 2.5 g/m 2 MFC.
  • Fig. 6D is a photograph of a spray coated (3 nozzles) unbleached Kraft paper surface at 2.5 g/m 2 MFC.
  • Fig. 6E is a photograph of a spray coated (3 nozzles) unbleached Kraft paper surface at 2.25 g/m 2 MFC.
  • the spray coating composition for all samples was microfibrillated cellulose / ground calcium carbonate (1: 1) composition applied onto an unbleached Kraft base paper.
  • Fig. 7 is a plot illustrating the Gurley porosity of microfibrillated cellulose coated sheets by total MFC coat weight in g/m' 2 .
  • Fig. 8 is a plot illustrating the heptane vapor transmission rate of microfibrillated cellulose coated sheets vs. total MFC coat weight in g/m' 2 .
  • Fig. 9A is a scanned image of a coarse particle size MFC surface coating on UBSK pulp sheets applied at 4 g/m' 2 .
  • Fig. 9B is a scanned image of two separate coarse particle size MFC surface coatings on UBSK pulp sheets applied at 2 + 2 g/m' 2 .
  • Fig. 9C is a scanned image of a fine particle size MFC surface coating on UBSK pulp sheets at 4 g/m' 2
  • Fig. 9D is a scanned image of two separate fine particle size MFC surface coatings on UBSK pulp sheets applied at 2 + 2 g/m' 2 .
  • Fig. 9A is a scanned image of a coarse particle size MFC surface coating on UBSK pulp sheets applied at 4 g/m' 2 .
  • Fig. 9B is a scanned image of two separate coarse particle size MFC surface coatings on UBSK pulp sheets applied at 2 + 2 g/m' 2 .
  • Fig. 9D is a
  • 9E is a scanned image of two different particle size MFC surface coatings on UBSK pulp sheets applied at 2 g/m' 2 coarse particle size MFC + 2 g/m' 2 fine particle size MFC.
  • Fig. 9F is a scanned image of two different particle size MFC surface coatings on UBSK pulp sheets applied at 2 g/m' 2 fine particle size MFC + 2 g/m' 2 coarse particle size MFC.
  • Fig. 10A is an SEM photograph of the surface of a base paper coated with a coarse particle size MFC composition at 4 g/m' 2 .
  • Fig. 10B is a photograph of a cross-section of a base paper coated with a coarse particle size MFC composition at 4 g/m' 2 .
  • Fig. 11 A is an SEM photograph of the surface of a base paper coated with a fine particle size MFC composition at 4 g/m' 2 .
  • Fig. 1 IB is a photograph of a cross-section of a base paper coated with a fine particle size MFC composition at 4 g/m' 2 .
  • Fig. 12A is an SEM photograph of the surface of a base paper coated with a eucalyptus MFC composition of high Fines B content at 2 g/m' 2 MFC followed by a eucalyptus MFC composition of low Fines B content 2 g/m' 2 MFC.
  • Fig. 12B is a photograph of a cross-section of a base paper coated with a low Fines B eucalyptus MFC composition at 2 g/m' 2 followed by a eucalyptus MFC composition of high Fines B content at 2 g m' 2 MFC.
  • FIG. 13A is an SEM photograph of the surface of a base paper coated with a low Fines B eucalyptus MFC composition coated onto the base paper at 2 g/m' 2 followed by a coating of a high Fines B eucalyptus MFC composition at 2 g/m' 2 .
  • Fig. 13B is an SEM photograph of a cross section of a low Fines B eucalyptus MFC composition coated onto a base paper at 2 g/m' 2 followed by a coating of a high Fines B eucalyptus MFC composition at 2 g/m' 2
  • Fig. 14 is a conceptual diagram of the progress of sample coating during a pilot trial of applying EVOH at the size press of a paper machine.
  • Fig. 15 is a side (cross-sectional) view of a paper or paperboard machine forming section equipped with a surface applicator comprising two slots capable of sequentially applying two nanocellulose-containing compositions, either the same or different coating compositions.
  • the first nanocellulose composition is applied to the consolidating base sheet at substantially the same time as the second nanocelluose-containing composition.
  • three or more slots may deliver 3 or more nanocellulose-containing compositions.
  • Fig. 16 is a side (cross-sectional) view of a paper or paperboard machine forming section equipped with a surface applicator comprising two slots capable of sequentially applying two nanocellulose-containing compositions, either the same or different coating compositions.
  • the first nanocellulose composition is applied to the consolidating base sheet prior to the application of the second nanocelluose-containing composition.
  • three or more slots may deliver 3 or more nanocellulose-containing compositions sequentially.
  • Fig. 17 is a side (cross-sectional) view of a paper or paperboard machine forming section equipped with two separate surface applicators comprising slotted applicators capable of sequentially applying two nanocellulose-containing compositions, either the same or different coating compositions.
  • the first nanocellulose composition is applied to the consolidating base sheet and is substantially drained before the second nanocellulose-containing composition is applied
  • Fig. 1 illustrates a paper or paperboard machine forming section equipped with a surface applicator and spray booms for sequential addition of nanocellulose-containing composition.
  • the paper or paperboard machine may be a Fourdrinier.
  • the paper or paperboard machine forming section is configured with a headbox 102 that distributes a continuous flow of stock at constant velocity, both across the width of the screen of the paper machine, as well as lengthwise.
  • the stock may be derived from cellulose-containing pulp, which may have been prepared by any suitable chemical or mechanical treatment, or combination thereof, which is well known in the art.
  • the pulp may be derived from any suitable source, such as wood, grasses (e.g., sugarcane and bamboo), or rags (e.g., textile waste, cotton, hemp, or flax).
  • the pulp may be bleached in accordance with processes that are well known to those skilled in the art. Those processes, suitable for use in the present disclosure, will be readily evident. In certain embodiments, the pulp may be unbleached.
  • the bleached or unbleached pulp may be beaten, refined, or both, to a predetermined freeness (reported in the art as Canadian standard freeness (CSF) in cm 3 or Schopper Riegler Freeness).
  • CSF Canadian standard freeness
  • the stock is then prepared from the bleached or unbleached and beaten pulp.
  • the stock may comprise or be derived from a Kraft pulp, which is naturally colored (i.e., unbleached). In certain embodiments, the stock may comprise or be derived from unbleached Kraft pulp, recycled pulp, or combinations thereof. In certain embodiments, the stock may comprise or be derived from recycled pulp.
  • the pulp may be obtained from chemical pulp, chemithermomechanical pulp, mechanical pulp, thermomechanical pulp (including, for example, Northern Bleached Softwood Kraft pulp (“NBSK”). Bleached hardwood pulp, and Bleached Chemi-Thermo Mechanical Pulp (“BCTMP”)), recycled pulp, paper broke pulp, papermill waste stream, waste from a papermill, or combinations thereof.
  • chemical pulp including, for example, Northern Bleached Softwood Kraft pulp (“NBSK”).
  • NBSK Northern Bleached Softwood Kraft pulp
  • BCTMP Bleached Chemi-Thermo Mechanical Pulp
  • the stock may contain other additives know n in the art.
  • the stock may contain anon-ionic, cationic, or anionic retention aid or microparticle retention system.
  • the stock may also or alternatively contain a sizing agent that may be, for example, a long chain alkylketene dimer (“AKD”). a wax emulsion or a succinic acid derivative (e.g., alkenylsuccinic anhydride (“ASA”)), and rosin plus alum or cationic rosin emulsions.
  • the stock may also or alternatively contain dye and/or an optical brightening agent.
  • the stock may also or alternatively comprise dry and/or wet strength aids such as, for example, starch or epichlorohydrin copolymer.
  • the stock may be a “thick stock,” meaning it includes about 4 w% solids. It may be mixed with recirculated whitewater from the machine before pumping to the headbox. Headbox solids are machine dependent.
  • the stock of the present disclosure may be from about 0.1 wt% to about 1 wt% solids. Sizing chemicals may be in the range of about 0.05 wt% to about 0.5 wt%, with retention aids being rather low er. Starch may be up to a few wt% of the stock.
  • the stock is output from the headbox 102 as a consolidating base sheet 104 (an example of a paper or paperboard substrate).
  • the consolidating base sheet 104 Upon exiting the headbox 102, the consolidating base sheet 104 is transported through a water removal stage of the paper or paperboard machine forming section. Within the water removal stage, the consolidating base sheet 104 may be transported over one or more dewatering elements 106 configured to remove w ater from the consolidating base sheet via suction.
  • a wet/dry line 108 is formed in the consolidating base sheet 104.
  • the consolidating base sheet 104 may be about 5 wt% to about 10 wt% solids at the wet/dry line 108.
  • the dewatering elements 106 may be one or more dew atering foils upstream of the wet/dry line 108 with respect to movement of the consolidating base sheet 104, and/or one or more vacuum boxes downstream of the w et/dry line 108 with respect to movement of the consolidating base sheet 104.
  • Example dewatering foils include, but are not limited to, silicon nitride foils and sialon ceramic foils.
  • the paper or paperboard machine forming section may include a slotted applicator 110, a first spray boom 114a, and a second spray boom 114b all in fluidic communication with a nanocellulose-containing composition delivery' system.
  • a “slotted applicator’" refers to an applicator configured to provide a layer of nanocellulose-containing composition to the surface of a consolidating base sheet.
  • Example slotted applicators include slot coaters and curtain coaters, which are each described in detailed herein below.
  • Each of the first spray boom 114a and the second spray boom 114b may include one or more spray nozzles 116.
  • the first spray boom 114a and the second spray boom 114b may have the same or differing numbers of spray nozzles 116.
  • the first spray boom 114a and the second spray boom 114b are not limited to have the number of spray nozzles 116 illustrated.
  • the slotted applicator 110, first spray boom 114a, and second spray boom 114b may each be in fluidic communication (via one or more delivery lines 118) with a nanocellulose- containing composition delivery system 120. For example, and as illustrated in Fig.
  • the slotted applicator 110, first spray boom 114a, and second spray boom 114b may all be in fluidic communication with the nanocellulose-containing composition delivery ⁇ system 120 via a single delivery line 118.
  • the slotted applicator 110 may be in fluidic communication with the nanocellulose-containing composition delivery system 120 via a first delivery line 118a
  • the first spray boom 114a and second spray boom 114b may both be in fluidic communication with the nanocellulose-containing composition delivery' system 120 via a second delivery line 118b.
  • the slotted applicator 110 may be in fluidic communication with the nanocellulose-containing composition delivery system 120 via a first delivery line 118a
  • the first spray boom 114a may be in fluidic communication with the nanocellulose-containing composition delivery system 120 via a second delivery line 118b
  • the second spray' boom 114b may be in fluidic communication with the nanocellulose-containing composition delivery' system 120 via a third delivery line 118c.
  • nanocellulose-containing composition is first applied to the consolidating base sheet 104 using the slotted applicator 1 10.
  • the nanocellulose-containing composition may first be applied to the consolidating base sheet 104 using curtain coating, in the situation where the slotted applicator 110 is a curtain coater, or slot coating in the situation where the slotted applicator 110 is a slot coater.
  • the nanocellulose-containing composition may be applied to the top of the consolidating base sheet 104 (after the wet/dry line) via a non-pressurized or pressurized slot opening in the slotted applicator 110.
  • the slotted applicator 110 may be a slot die coater.
  • the consolidating base sheet 104, having the first layer of the nanocellulose- containing composition applied thereto, may be passed over one or more dewatering elements 106 prior to at least a second layer of the nanocellulose-containing composition being applied to the top surface of the consolidating base sheet 104.
  • the consolidating base sheet 104 having the first layer of the nanocellulose-containing composition applied thereto, may be passed over one or more dewatering elements 106 prior to a second layer of the nanocellulose-containing composition being applied to the top surface of the consolidating base sheet 104.
  • the first layer of the nanocellulose-containing composition may be applied via curtain or slot coating (i.e., via the slotted applicator 110), and the second layer of the nanocellulose-containing composition may be applied via spraying.
  • the second layer of the nanocellulose-containing composition may be applied via the first spray boom 114a having one or more spray nozzles 116.
  • the number and configuration of the spray nozzle(s) 116, of the first spray boom 114a may be configured to apply the second layer of the nanocellulose-containing composition to the entire (or substantially the entire) width of the consolidating base sheet 104 having the first layer of the nanocellulose- containing composition already applied thereto.
  • the spray nozzles 116 may cause the nanocellulose-containing composition to exhibit a particular spray profile 122.
  • the spray profile 122 may be conical.
  • the spray profile 122 may be linear.
  • the consolidating base sheet 104 having the first and second layers of the nanocellulose-containing composition applied thereto, may be passed over one or more dewatering elements 106 (e g., vacuum boxes) prior to at least a third layer of the nanocellulose-containing composition being applied to the top surface of the consolidating base sheet 104.
  • the consolidating base sheet 104 having the first and second layers of the nanocellulose-containing composition applied thereto, may be passed over one or more dewatering elements 106 (e.g., vacuum boxes) prior to a third layer of the nanocellulose- containing composition being applied to the top surface of the consolidating base sheet 104.
  • dewatering elements 106 e.g., vacuum boxes
  • the first layer of the nanocellulose-containing composition may be applied via curtain or slot coating (i.e., via the slotted applicator 110), and the second and third layers of the nanocellulose-containing composition may be applied via spraying.
  • the third layer of the nanocellulose-containing composition may be applied via the second spray boom 114b having one or more spray nozzles 116.
  • the number and configuration of the spray nozzle(s) 116 of the second spray boom 114b may be configured to apply the third layer of the nanocellulose-containing composition to the entire (or substantially the entire) width of the consolidating base sheet 104 having the first and second layers of the nanocellulose-containing composition already applied thereto.
  • Fig. 1 is to be interpreted as teaching sequential application of a (single) nanocellulose-containing composition to a consolidating base sheet, where a first application of the nanocellulose-containing composition involves curtain or slot coating, and one or more subsequent applications (e g., just a second application; a second and third application; a second, third, and fourth application, etc.) of the nanocellulose-containing composition involves spraying.
  • the spray nozzles of the different booms may be aligned with respect to movement of the consolidating base sheet.
  • the spray nozzles of one boom may be offset (along a direction of movement of the consolidating base sheet) with respect to spray nozzles of a different boom. In some instances, this offset configuration of spray nozzles may achieve a more uniform coverage of the nanocellulose-containing composition along the width of the consolidating base sheet.
  • the consolidating base sheet 104 may be transported over one or more additional dewatering elements 106 (e.g., vacuum boxes) to achieve a paper or paperboard having a sufficient dryness.
  • additional dewatering elements 106 e.g., vacuum boxes
  • the consolidating base sheet 104 may be transported over three additional dewatering elements 106.
  • the consolidating base sheet 104 may undergo edge trimming 124 to trim the consolidating base sheet 104 to a desired width.
  • the edge trimming 124 may be water jet edge trimming.
  • the consolidating base sheet 104 may be transported over one or more dewatering elements 106 (e g., vacuum boxes) after the consolidating base sheet 104 undergoes edge trimming 124.
  • the consolidating base sheet 104 may be transported over two and a half dewatering elements 106 following edge trimming 124.
  • the consolidating base sheet 104 may undergo sheet transfer 126 to a couch roll 128.
  • Fig. 2 provides an alternative configuration of the paper or paperboard machine forming section.
  • the above disclosure of Fig. 1 is applicable to Fig. 2, except for the following differences.
  • Fig. 1 relates to a paper or paperboard machine forming section configured for sequential application of a nanocellulose-containing composition to a consolidating base sheet 104, where a first application of the nanocellulose-containing composition involves curtain or slot coating, and one or more subsequent applications (e g., just a second application; a second and third application; a second, third, and fourth application, etc.) of the nanocellulose-containing composition involves spraying.
  • Fig. 2 illustrates a paper or paperboard machine forming section configured for sequential application of a nanocellulose-containing composition to a consolidating base sheet 104, where all applications of the nanocellulose-containing composition occur via spraying.
  • Fig. 2 shows use of a first spray boom 114a, a second spray boom 114b, a third spray boom 114c, and a fourth spray boom 114d
  • the disclosure is not limited thereto. Rather, one skilled in the art will appreciate that Fig. 2 is to be interpreted as teaching sequential application of two or more layers of a nanocellulose-containing composition to a consolidating base sheet, where each of the two or more application layers occur via spraying.
  • Fig. 3 provides yet another alternative configuration of the paper or paperboard machine forming section.
  • the above disclosure of Fig. 1 is applicable to Fig. 3, except for the following differences.
  • Fig. 1 relates to a paper or paperboard machine forming section configured for sequential application of two or more layers (the first being via curtain or slot coating, and the at least second being via spraying), of a single nanocellulose-containing composition, are applied to the consolidating base sheet 104.
  • Fig. 3 illustrates a paper or paperboard machine forming section configured for sequential application of two or more nanocellulose-containing compositions to the consolidating base sheet 104.
  • the slotted applicator 110 may be in fluidic communication with a first nanocellulose-containing composition delivery system 120a (configured to deliver a first nanocellulose-containing composition), and the first spray boom 114a and the second spray boom 114b may be in communication with a second nanocellulose-containing composition delivery system 120b (configured to deliver a second nanocellulose-containing composition).
  • the slotted applicator 110 may be in fluidic communication with the first nanocellulose-containing composition delivery system 120a via a first delivery line 118a
  • the first spray boom 114a and the second spray boom 114b may both be in fluidic communication with the second nanocellulose-containing composition delivery' system 120b via a second delivery line 118b.
  • first spray boom 114a may be in fluidic communication with the second nanocellulose-containing composition delivery' system 120b via the second delivery' line 118b
  • second spray boom 114b may be in fluidic communication with the second nanocellulose-containing composition delivery' system 120b via a third delivery line 118c.
  • Fig. 3 illustrates the slotted applicator 1 10 being in fluidic communication w ith the first nanocellulose-containing composition delivery system 120a, and the first spray boom 114a and the second spray boom 114b being in fluidic communication with the second nanocellulose-containing composition delivery system 120b
  • the present disclosure is not limited thereto.
  • at least one spray boom e.g., at least one of the first spray boom 1 14a or the second spray boom 1 14b, or a non-illustrated spray boom
  • Fig. 4 provides yet a further configuration of the paper or paperboard machine forming section.
  • the above disclosure of Fig. 2 is applicable to Fig. 4, except for the following differences.
  • Fig. 2 relates to a paper or paperboard machine forming section configured for sequential application of a single nanocellulose-containing composition to a consolidating base sheet, where all applications of the nanocellulose-containing composition occur via spraying.
  • Fig. 4 illustrates a paper or paperboard machine forming section configured for sequential application of two or more nanocellulose-containing compositions to the consolidating base sheet 104.
  • the first spray boom 114a and the second spray boom 114b may be in fluidic communication with the first nanocellulose-containing composition delivery system 120a, and the third spray boom 114c and the fourth spray boom 114d may be in communication with the second nanocellulose-containing composition delivery 7 system 120b.
  • the first spray boom 114 and the second spray boom 114b may be in fluidic communication with the first nanocellulose-containing composition delivery system 120a via the first delivery line 118a, and the third spray boom 114c and the fourth spray boom 114d may both be in fluidic communication with the second nanocellulose-containing composition delivery system 120b via the second delivery 7 line 118b.
  • first spray boom 114a and the second spray boom 114b may be in fluidic communication with the first nanocellulose-containing composition delivery system 120a via different delivery lines, and/or the third spray boom 114c and the fourth spray boom 114d may be in fluidic communication with the second nanocellulose-containing composition delivery 7 system 120b via different delivery lines.
  • Fig. 4 is to be interpreted to cover a paper or paperboard machine forming section in which at least one spray boom is configured to apply at least one layer of a first nanocellulose-containing composition to the consolidating base sheet 104, and at least one other spray boom is configured to apply at least one layer of a second nanocellulose-containing composition to the consolidating base sheet 104.
  • a slotted applicator 110 is used to apply nanocellulose- containing composition prior to spraying.
  • spraying may be used to apply nanocellulose-containing composition(s) prior to curtain or slot coating using the slotted applicator 1 10.
  • one or more instances of curtain or slot coating, using slotted applicators 110 may be used in between two instances of spraying.
  • one or more instances of spraying may be used in between two instances of curtain or slot coating using slotted applicators 110.
  • the exact configuration, in which nanocellulose-containing composition(s) is applied, is configurable.
  • slot coating apparatuses, systems, and techniques are known to those skilled in the art. The present disclosure envisions use of art- and industry-known slot coating apparatuses, systems, and techniques, as well as those not yet known or discovered.
  • An example slot coating technique that may be used in accordance with the present disclosure is that described in U.S. patent no. 10,550,520, issued on February 4, 2020, and entitled “Method With a Horizontal Jet Applicator for a Paper Machine Wet End.” the entirety of which is hereby incorporated by reference.
  • the slotted applicator 110 may have a channel in fluidic communication with a horizontal slot having a vertical gap height (in some instances less than 0.100 inch). Nanocellulose-containing composition is pumped through the channel and to the horizontal slot. In some instances, the nanocellulose-containing composition is pumped at a rate of less than 5 US gallons per minute per inch of the slot.
  • the additive leaves the slot in a substantially horizontal direction above the consolidating base sheet 104 traveling in a substantially horizontal direction.
  • This vertical gap height should be set to get the required flow at a speed needed to maintain a good formation.
  • the nanocellulose-containing composition is forced out of the narrow slot in the slotted applicator 110 as a full-width, essentially horizontal jet and lands on the consolidating base sheet 104 of the paper machine.
  • a vertical layer of nanocellulose-containing composition, falling by gravity, has a much lower machine direction velocity than the consolidating base sheet 104 on which it lands, which may cause significant extension of the nanocellulose-containing composition layer, as well as stresses and disruptions both in this layer and in the top surface of the consolidating base sheet 104.
  • Pressurizing the slotted applicator 1 10 to increase the velocity of the vertically falling nanocellulose-containing composition may cause the nanocellulose- containing composition to partially penetrate and disrupt the forming consolidating base sheet 104 as it lands.
  • a slot coater having a pressurized slot for dispensing of nanocellulose- containing composition, is angled away from true vertical.
  • the slot coater may be cofigured such that the flow of the nanocellulose-containing composition, from an expansion chamber, passes through a narrow, essentially parallel slot that is oriented in a horizontal, or nearly horizontal, direction to the consolidating base sheet 104, and forms a full width jet which then lands on the consolidating base sheet 104.
  • By adjusting the pressure in the slot coater and the slot gap height it is possible to adjust the velocity of the essentially horizontal jet relative to the velocity of the consolidating base sheet 104, and therefore to land the jet of nanocellulose-containing composition on the consolidating base sheet 104 without disruption.
  • the slot coater may have long, essentially parallel lips that form the slot and have an angle between the top and bottom surfaces of less than 3 degrees.
  • the slot coater may include a knuckle and jack mechanism, allowing for opening and closing of a lip holder to assist in maintenance of the slot coater.
  • the nanocellulose-containing composition may enter a distribution chamber, where it then passes through spaced apart tubes into an expansion chamber. From there, the nanocellulose-containing composition may accumulate to insure even distribution through a channel into a nozzle chamber. From the nozzle chamber, the nanocellulose-containing composition may get distributed evenly across and through a slot formed by the substantially parallel lips, so the nanocellulose-containing composition falls evenly onto the mobile consolidating base sheet 104.
  • curtain coating apparatuses, systems, and techniques are known to those skilled in the art. The present disclosure envisions use of art- and industry-known curtain coating apparatuses, systems, and techniques, as well as those not yet known or discovered.
  • a curtain coater includes the same components as the slot coater described above, except a curtain coater's slot (which may nor may not be pressurized) is oriented vertically with respect to the consolidating base sheet 104 (as compared to horizontally or nearly horizontally oriented as is a slot coater’s slot).
  • curtain coating may have some drawbacks, curtain coating may nonetheless be sufficient in at least some contexts to apply a layer of nanocellulose-containing composition as described herein.
  • FIG. 15 depicts a single slot coater 210 with two slots 205a and 205b.
  • Delivery lines 21 la and 21 lb provide conduits for delivering nanocellulose-containing compositions 212a and 212b, which compositions may be the same or different.
  • the paper or paperboard machine forming section 200 is equipped with a slotted applicator 210 comprising two slots 205a and 205b capable of sequentially applying two nanocellulose-containing compositions, either the same or different coating compositions.
  • the first nanocellulose composition is applied to the consolidating base sheet 201 deposited on a forming fabric 202 at substantially the same time as the second nanocelluose-containing composition.
  • three or more slots may deliver 3 or more nanocellulose-containing compositions.
  • the slotted applicator 210 is designed to apply two coating layers on the consolidating base sheet 201 which is deposited on the forming fabric 202 of the paperboard machine.
  • the slotted coater can thereby apply multilayers of the same or different coatings.
  • the layers of nanocellulose coating land on the consolidating base sheet and consolidating substrate simultaneously to drain and consolidate together.
  • Fig. 16 depicts a single slot coater 310 with two slots 305a and 305b.
  • Delivery lines 311a and 311b provide conduits for delivering nanocellulose-containing compositions 312a and 312b, which compositions may be the same or different.
  • the paper or paperboard machine forming section 300 is equipped with a slotted applicator comprising two slots 305a and 305b capable of sequentially applying two nanocellulose-containing compositions, either the same or different coating compositions. In this configuration the first nanocellulose composition is applied to the consolidating base sheet 301 deposited on a forming fabric 302 prior to the second nanocelluose-containing composition.
  • the slotted applicator 310 is designed to apply two coating layers on the consolidating base sheet 301 which is deposited on the forming fabric 302 of the paperboard machine.
  • the slotted coater can thereby apply multilayers of the same or different coatings.
  • the first nanocellulose-coating composition 312a is applied to the consolidating base sheet 301 before the second nanocellulose- containing composition 312b is applied.
  • the applicator can apply multiple layers of the same or different nanocellulose-containing compositions.
  • the first nanocellulose composition 312a is applied to the consolidating substrate 301 and is substantially drained before the second nanocellulose-containing composition 312b is applied.
  • three or more slots may deliver 3 or more nanocellulose-containing compositions.
  • Fig. 17 is a side view of a paper or paperboard machine forming section equipped with two separate surface applicators comprising slotted applicators capable of sequentially applying two nanocellulose-containing compositions, either the same or different coating compositions.
  • the first nanocellulose composition is applied to the consolidating base sheet and is substantially drained before the second nanocellulose- containing composition is applied.
  • Fig. 17 depicts two slot coaters 410a and b, each with a single slot 405 and 405b.
  • Delivery lines 4 I la and 411b provide conduits for delivering nanocellulose-containing compositions 412a and 412b, which compositions may be the same or different.
  • the paper or paperboard machine forming section 400 is equipped with a slotted applicator comprising slots 405 a and 405b, respectively, which are capable of sequentially applying two nanocellulose-containing compositions, either the same or different coating compositions.
  • the first nanocellulose composition is applied to the consolidating base sheet 401 deposited on a forming fabric 402 prior to the second nanocelluose-containing composition.
  • the slotted applicators 410a and 410b are designed to apply two coating layers on the consolidating base sheet 401 which is deposited on the forming fabric 402 of the paperboard machine.
  • the slotted coater can thereby apply multilayers of the same or different coatings.
  • the first nanocellulose-coating composition 412a is applied to the consolidating base sheet 401 before the second nanocellulose- containing composition 412b is applied.
  • the applicator can apply multiple layers of the same or different nanocellulose-containing compositions.
  • the first nanocellulose composition 412a is applied to the consolidating substrate 401 and is substantially drained before the second nanocellulose-containing composition 412b is applied.
  • three or more slots may deliver 3 or more nanocellulose-containing compositions. Spraying
  • nozzles used to spray nanocellulose-containing composition, may produce a flat “fan” spray.
  • the orifice of a spray nozzle may be roughly elliptical but having sharp edges.
  • Various pressures may also be utilized to achieve the effects and benefits set forth in the present disclosure.
  • a pressure between about 10 psi and about 50 psi may be utilized.
  • the pressure utilized may depend, at least in part, on the nozzle configuration utilized.
  • Some nozzles have codes, such as 95-30, where the first number refers to the angle of the spray at 40 psi and the second refers to the US gallons per minute at 40 psi (multiplied by 10). So, for example, the code 95-30 has a wide, 95 spray angle and delivers 3 gallons/min at 40 psi.
  • nanocellulose-containing composition comprises nanocellulose.
  • nanocellulose refers to cellulose structures with one dimension (e.g., diameter) in the sub-micron region (i.e., ⁇ 1 pm).
  • the nanocellulose may include cellulose nanofiber (CNF).
  • CNF refers to cellulose structures having a diameter of about 5 nm to about 10 nm, and an average length of about 50 nm to about 100 nm.
  • wood may be crushed into woodchips of about 5 cm in width and 1 cm in thickness.
  • fibers are extracted from the woodchips and pulped. The pulp is then chemically processed to produce fibers, which may then be further chemically or enzy matically treated to make them easier to separate into their constituent fibrils.
  • the nanocellulose may include nanofibrillated cellulose (NFC).
  • NFC refers to cellulose fibers that have been fibrillated (via mechanical disintegration) to achieve agglomerates of cellulose microfibril units.
  • NFC has nanoscale (e.g., ⁇ 100 nm) diameter, and a typical length of several micrometers.
  • NFC may be produced from various cellulosic sources including, but not limited to, wood, bleached kraft pulp, bleached sulfite pulp, sugar beet pulp, wheat straw and soy hulls, sisal, bagasse, palm trees, ramie, carrots, and luffa cylindrica.
  • NFC may be produced using various mechanical disintegration processes and systems such as, but not limited to, a homogenizer system, a microfluidizer, and a grinder.
  • the nanocellulose may include cellulose nanocrystals (CNCs).
  • CNCs are a derivative of cellulose, which can be obtained through acid hydrolysis of cellulose, where the cellulose is exposed to (e.g., sulfuric) acid under controlled temperature for a time period. The acid hydrolysis dissolves the amorphous regions of cellulose, but leaves the crystalline regions largely intact, hence the production of nanocrystals.
  • CNCs can be isolated from various renewable resources such as plants (e.g., cotton and wood), bacteria, and sea animals. Depending on the isolation method utilized and the source of the cellulose, CNCs can range from 5 nm to 30 nm in diameter, and have aspect ratios up to about 100. CNCs can have high specific strength and Young's modulus. Moreover, the active hydroxyl surface groups of CNCs enable chemical functionalization.
  • the nanocellulose may include microfibrillated cellulose (MFC).
  • MFC microfibrillated cellulose
  • ‘'microfibrillated cellulose” and “MFC” both refer to a material containing nanoscale fibrils that have been partially or completely separated from their parent fibers.
  • microfibrillated cellulose may have at least one dimension less than about 100 nm.
  • MFC comprises partly or totally fibrillated cellulose or lignocellulose fibers. The liberated fibrils have a diameter less than about 100 nm, whereas the actual fibril diameter or particle size distribution and/or aspect ratio (length/width) depends on the source and the manufacturing methods.
  • the smallest fibril is called elementary fibril and has a diameter of approximately 2 nm to 4 nm (see. e.g., Chinga-Carrasco, G., Cellulose fibres, nanofibrils and microfibrils: The morphological sequence of MFC components from a plant physiology and fibre technology point of view, Nanoscale Research Letters 2011, 6:417), while it is common that the aggregated form of the elementary fibrils, also defined as microfibril (see, e.g., Fengel, D., Ultrastructural behavior of cell wall polysaccharides, Tappi J., March 1970, Vol 53. No.
  • MFC is the main product that is obtained when making MFC (e.g., by using an extended refining process or pressure-drop disintegration process).
  • the length of the fibrils can vary from around 1 pm to more than 10 pm.
  • a coarse MFC grade might contain a substantial fraction of fibrillated fibers (i.e., protruding fibrils from the tracheid (cellulose fiber)), and with a certain amount of fibrils liberated from the tracheid (cellulose fiber).
  • MFC can also be characterized by various physico-chemical properties, such as large surface area or its ability to form a gel-like material at low solid contents (e.g., 1 wt% to 5 wt%) when dispersed in water.
  • the cellulose fiber is preferably fibrillated to such an extent that the final specific surface area of the formed MFC is from about 1 m 2 /g to about 300 m 2 /g, such as from about 1 m 2 /g to about 200 m 2 /g, or more preferably about 50 nf/g to about 200 m 2 /g, when determined for a freeze-dried material with the Brunauer, Emmett, and Teller (BET) method.
  • BET Brunauer, Emmett, and Teller
  • the MFC may have a Schopper Riegler value (SR.degree.) of more than about 85 SR. degree, more than about 90 SR.degree, or more than about 92 SR.degree.
  • the Schopper-Riegler value can be determined through the standard method defined in EN ISO 5267-1.
  • MFC may be characterized by its mean particle size.
  • One technique for measuring the mean particle size of MFC involves laser light scattering, using a Malvern Insitec machine as supplied by Malvern Instruments Ltd (or other methods that give essentially the same result).
  • the size of particles in powders, suspensions, and emulsions may be measured using the diffraction of a laser beam, based on an application of Mie theory.
  • Such a machine provides measurements and a plot of the cumulative percentage by volume of particles having an “equivalent spherical diameter” (e.s.d.), less than given e.s.d. values.
  • the mean particle size dso is the value determined in this way of the particle e.s.d. at which there are 50% by volume of the particles which have an equivalent spherical diameter less than that d n value.
  • the following is an example procedure for determining particle size distribution of MFC as measured by a Malvern Insitec L light scattering device.
  • a 850 micron screen may be used to remove the grinding media before running the Malvern analysis. If no grinding medium is present, the slurry may be pipetted from the sample.
  • the MFC may have a dso value ranging from about 1 pm to about 500 pm, as measured by laser light scattering.
  • the MFC may have a d.so value equal to or less than about 400 pm, equal to or less than about 300 pm, equal to or less than about 200 pm, equal to or less than about 150 pm, equal to or less than about 125 pm, equal to or less than about 100 pm, equal to or less than about 90 pm, equal to or less than about 80 pm. equal to or less than about 70 pm. equal to or less than about 60 pm, equal to or less than about 50 pm, equal to or less than about 40 pm, equal to or less than about 30 pm, equal to or less than about 20 pm, or equal to or less than about 10 pm.
  • the MFC may have a modal fibre particle size ranging from about 0. 1 pm to about 500 pm, and a modal inorganic particulate material particle size ranging from about 0.25 pm to about 20 pm.
  • the MFC may have a modal fibre particle size of at least about 0.5 pm, at least about 10 pm, at least about 50 pm, at least about 100 pm, at least about 150 pm, at least about 200 pm, at least about 300 pm, or at least about 400 pm.
  • the MFC may additionally or alternatively be characterized in terms of fibre steepness.
  • Fibre steepness i.e., the steepness of the particle size distribution of the fibres in the MFC
  • the MFC may have a fibre steepness equal to or less than about 100, equal to or less than about 75, equal to or less than about 50, equal to or less than about 40, or equal to or less than about 30. In some embodiments, the MFC may have a fibre steepness of about 20 to about 50.
  • MFC may be characterized by fibre length (Lc(w) ISO).
  • the MFC may have a fibre length of less than about 0.7 mm, less than about 0.6 mm, less than about 0.5 mm, less than about 0.4 mm, less than about 0.3 mm, less than about 0.2 mm, or less than about 0.1 mm as measured by a fiber image analyzer.
  • the MFC may have a fibre length of less than about 0.7 mm.
  • Nanocellulose may contain some hemicelluloses, of which the amount is dependent on the plant source.
  • Mechanical disintegration of the pre-treated fibers e.g. hydrolysed, preswelled, or oxidized cellulose raw material
  • suitable equipment such as a refiner, grinder, homogenizer, colloider, friction grinder, ultrasound sonicator, fluidizer such as microfluidizer, macrofluidizer or fluidizer-type homogenizer.
  • Nanocellulose might also contain fines or other chemicals present in wood fibers or in papermaking process. Nanocellulose might also contain various amounts of micron size fiber particles that have not been efficiently fibrillated.
  • Nanocellulose may be produced from wood cellulose fibers, both from hardwood or softwood fibers. Nanocellulose can also be made from microbial sources, agricultural fibers such as wheat straws pulp, bamboo, bagasse, or other non-wood fiber sources. Nanocellulose may also be made from pulp including pulp from virgin fiber (e.g., mechanical, chemical, and/or thermomechanical pulps).
  • the nanocellulose may be obtained from a chemical pulp, or a chemithermomechanical pulp, or a mechanical pulp, or thermomechanical pulp, including, for example, Northern Bleached Softwood Kraft pulp (“NBSK ”), Bleached Chemi-Thermo Mechanical Pulp (“BCTMP”), a recycled pulp, a paper broke pulp, a paper mill waste stream, or a combination thereof.
  • NBSK Northern Bleached Softwood Kraft pulp
  • BCTMP Bleached Chemi-Thermo Mechanical Pulp
  • the pulp source may be kraft pulp, or bleached long fibre kraft pulp.
  • the pulp source may be softwood pulp selected from spruce, pine, fir, larch and hemlock or mixed softwood pulp.
  • the pulp source may be hardw ood pulp selected from eucalyptus, aspen and birch, or mixed hardwood pulps.
  • the pulp source may be eucalyptus pulp, spruce pulp, pine pulp, beech pulp, hemp pulp, acacia cotton pulp, and mixtures thereof.
  • Nanocellulose may be derived from recycled pulp or a papermill broke and/or industrial w aste, or a paper stream rich in mineral fillers and cellulosic materials from a papermill.
  • the recycled cellulose pulp may be beaten (e.g., in a Valley beater) and/or otherwise refined (e.g., processing in a conical or plate refiner) to any predetermined freeness, reported in the art as Canadian standard freeness (CSF) in cm 3 or Schopper Riegler Freeness.
  • CSF means a value for the freeness or drainage rate of pulp measured by the rate that a suspension of pulp may be drained, and this test is carried out according to the T 227 cm-09 TAPPI standard.
  • the cellulose pulp may have a CSF of about 10 cm 3 or greater prior to undergoing processing into nanocellulose.
  • the recycled cellulose pulp may- have a CSF of about 700 cm 3 or less, for example, equal to or less than about 650 cm 3 , equal to or less than about 600 cm 3 , equal to or less than about 550 cm 3 , equal to or less than about 500 cm 3 , equal to or less than about 450 cm 3 , equal to or less than about 400 cm 3 , equal to or less than about 350 cm 3 , o equal to or less than about 300 cm 3 , equal to or less than about 250 cm 3 , equal to or less than about 200 cm 3 , equal to or less than about 150 cm 3 , equal to or less than about 100 cm 3 , or equal to or less than about 50 cm 3 .
  • the recycled cellulose pulp may have a CSF of about 20 to about 700.
  • the recycled cellulose pulp may then be dewatered bymethods well known in the art, for example, the pulp may be filtered through a screen in order to obtain a wet sheet comprising at least about 10% solids, for example at least about 15% solids, at least about 20% solids, at least about 30% solids, or at least about 40% solids.
  • Methods of manufacturing MFC include mechanical disintegration by- refining, milling, beating and homogenizing, and refining, for example, by an extruder. These mechanical measures may be enhanced by chemical or chemo-enzy matic treatments as a preliminary- step.
  • Various known methods of microfibrillation of cellulosic fibres are summarized in U.S. Pat. No. 6,602,994 Bl as including, for example, homogenization, steam explosion, pressurization-depressurization, impact, grinding, ultrasound, microwave explosion, milling and combinations of these.
  • WO 2007/001229 discloses enzy me treatment and, as a method of choice, oxidation in the presence of a transition metal for turning cellulosic fibres to MFC.
  • the material is disintegrated by mechanical means.
  • a combination of mechanical and chemical treatment can also be used.
  • chemicals that can be used are those that either modify the cellulose fibers through a chemical reaction or those that modify the cellulose fibers via, for example, grafting or sorption of chemicals onto/into the fibers.
  • WO 2007/091942 Al describes a process in which chemical pulp is first refined, then treated with one or more wood degrading enzymes, and finally homogenized to produce MFC as the final product.
  • the consistency of the pulp is described to be preferably from about 0.4% to about 10%.
  • the advantage is said to be avoidance of clogging in the high-pressure fluidizer or homogenizer.
  • W02010/131016 describes a grinding procedure for the production of MFC with or without inorganic particulate material. Such a grinding procedure is described below.
  • the process utilizes mechanical disintegration of cellulose fibres to produce MFC cost-effectively and at large scale, without requiring cellulose pre-treatment.
  • An embodiment of the method uses stirred media detritor grinding technology, which disintegrates fibres into MFC by agitating grinding media beads.
  • an inorganic particulate material such as calcium carbonate or kaolin, is added as a grinding aid, greatly reducing the energy required.
  • a stirred media mill consists of a rotating impeller that transfers kinetic energy to small grinding media beads, which grind down the charge via a combination of shear, compressive, and impact forces.
  • a variety of grinding apparatus may be used to produce MFC by the disclosed methods herein, including, for example, a tower mill, a screened grinding mill, or a stirred media detritor.
  • microfibrillation of a fibrous substrate comprising cellulose may be effected under wet conditions in the presence of the inorganic particulate material by a method in which the mixture of cellulose pulp and inorganic particulate material is pressurized (for example, to a pressure of about 500 bar) and then passed to a zone of lower pressure.
  • the rate at which the mixture is passed to the low-pressure zone is sufficiently high and the pressure of the low pressure zone is sufficiently low to cause microfibrillation of the cellulose fibres.
  • the pressure drop may be affected by forcing the mixture through an annular opening that has a narrow entrance orifice with a much larger exit orifice.
  • microfibrillation of the fibrous substrate comprising cellulose may be affected in a homogenizer under wet conditions in the presence of the inorganic particulate material.
  • the cellulose pulp-inorganic particulate material mixture is pressurized (for example, to a pressure of about 500 bar), and forced through a small nozzle or orifice.
  • the mixture may be pressurized to a pressure of from about 100 to about 1000 bar, for example to a pressure equal to or greater than 200 bar, equal to or greater than about 300 bar, equal to or greater than about 500, or equal to or greater than about 700 bar.
  • the homogenization subjects the fibres to high shear forces such that as the pressurized cellulose pulp exits the nozzle or orifice, cavitation causes microfibrillation of the cellulose fibres in the pulp.
  • Water may be added to improve flowability of the suspension through the homogenizer.
  • the resulting aqueous suspension comprising MFC and inorganic particulate material may be fed back into the inlet of the homogenizer for multiple passes through the homogenizer.
  • the inorganic particulate material is a naturally platy mineral, such as kaolin. As such, homogenization not only facilitates microfibrillation of the cellulose pulp, but also facilitates delamination of the platy inorganic particulate material.
  • a platy inorganic particulate material such as kaolin, is understood to have a shape factor of at least about 10, at least about 15, at least about 20, at least about 30, at least about 40, at least about 50, at least about 60, at least about 70, at least about 80, at least about 90, or at least about 100.
  • Shape factor is a measure of the ratio of particle diameter to particle thickness for a population of particles of vary ing size and shape as measured using the electrical conductivity methods, apparatuses, and equations described in U.S. Patent No. 5,576,617, which is incorporated herein by reference.
  • NFC production techniques are disclosed in U.S. Patent Application Publication No. 17/193,376, entitled “Process for the Production of Nano-Fibrillar Cellulose Gels,” to Gane et al. ,- U.S. Patent No. 10,975,242, “Process for the Production of Nano-Fibrillar Cellulose Gels,” to Gane el al. ; U.S. Patent No. 10,294,371, “Process for the Production of Nano- Fibrillar Cellulose Gels,” to Gane et al. U.S. Patent No. 8,871.056.
  • a nanocellulose-containing composition of the present disclosure may include nanocellulose in var ing amounts.
  • reference to the “total weight of the nanocellulose-containing composition” includes all components of the nanocellulose- containing composition including the weight of all liquids present, unless otherwise stated.
  • Nanocellulose may be present in an amount of at least about 0.01 wt%, 0.05 wt%, 0.1 wt%, 0.15 wt%, 0.2 wt%, 0.25 wt%, 0.3 wt%, 0.35 wt%, 0.4 wt%, 0.45 wt%, or 0.5 wt%, of the total weight of the nanocellulose-containing composition.
  • the nanocellulose may be present in an amount of at least about 0.2 wt% of the total weight of the nanocellulose-containing composition. In some embodiments, the nanocellulose may be present in an amount of at least about 0.5 wt% of the total weight of the nanocellulose- containing composition.
  • Nanocellulose may be at most about 1 wt%, 1.05 wt%, 1.10 wt%, 1.15 wt%, 1.20 wt%. 1.25 wt%, 1.30 wt%. 1.35 wt%, 1.40 wt%, 1.45 wt%. 1.50 wt%, 1.55 wt%.
  • the nanocellullose may be present in an amount of at most about 6 wt% of the total weight of the nanocellulose-containing composition. In some embodiments, the nanocellullose may be present in an amount of at most about 5 wt% of the total weight of the nanocellulose-containing composition. In some embodiments, the nanocellullose may be present in an amount of at most about 4 wt% of the total weight of the nanocellulose- containing composition.
  • the nanocellullose may be present in an amount of at most about 3 wt% of the total weight of the nanocellulose-containing composition. In some embodiments, the nanocellullose may be present in an amount of at most about 2 wt% of the total weight of the nanocellulose-containing composition.
  • the nanocellulose may be about 0.5% wt% to about 6 wt% of the total weight of the nanocellulose-containing composition.
  • the nanocellulose may be about 1 wt% to about 2 wt% of the total weight of the nanocellulose-containing composition.
  • Nanocellulose may be present in an amount of at least about 0.01 wt%, 0.05 wt%, 0. 1 wt%, 0.15 wt%, 0.2 wt%, 0.5 wt%, 0.7 wt%, or 1.0 wt%, 1.5 wt%, 2.5 wt%, 5 wt%, 10 wt%, 15 wt%, 20 wt%, 25 wt%, 30 wt%, 35 wt%, 40 wt%, 45 wt%, or 50 wt%, of the total solid content of the nanocellulose-containing composition.
  • the nanocellulose may be present in an amount of at least about 40 wt% of the total solid content of the nanocellulose-containing composition. In some embodiments, the nanocellulose may be present in an amount of at least about 50 wt% of the total solid content of the nanocellulose-containing composition.
  • a nanocellulose-containing composition of the present disclosure may include one or more inorganic particulate materials.
  • the inorganic particulate material when present, may, for example, be an alkaline earth metal carbonate or sulphate, such as calcium carbonate, magnesium carbonate, dolomite, gypsum, a clay such as hydrous kandite clay such as kaolin, halloysite or ball clay, bentonite, an anhydrous (calcined) kandite clay such as metakaolin or fully calcined kaolin, talc, mica, perlite or diatomaceous earth, or magnesium hydroxide, or aluminum trihydrate, or combination thereof.
  • the nanocellulose-containing composition may include calcium carbonate, clay, aluminum trihydrate, or a combination thereof.
  • the calcium carbonate may be ground calcium carbonate (GCC).
  • GCC is typically obtained by crushing and then grinding an inorganic particulate material source such as chalk, marble, or limestone, which may be followed by a particle size classification step, in order to obtain a product having the desired degree of fineness.
  • Other techniques such as bleaching, flotation, and magnetic separation may also be used to obtain a product having the desired degree of fineness and/or color.
  • the particulate solid material may be ground autogenously (i.e., by attrition between the particles of the solid material themselves, or, alternatively, in the presence of a particulate grinding medium comprising particles of a different material from the calcium carbonate to be ground). These processes may be carried out with or without the presence of a dispersant and biocides, which may be added at any stage of the process.
  • the calcium carbonate may be precipitated calcium carbonate (PCC).
  • PCC may be used as the source of particulate calcium carbonate in the nanocellulose disclosed herein, and may be produced by any of the know n methods available in the art.
  • TAPPI Monograph Series No 30, "Paper Coating Pigments", pages 34-35 describes the three main commercial processes for preparing precipitated calcium carbonate which is suitable for use in preparing products for use in the paper industry, but may also be used in the practice of the present disclosure. In all three processes, a calcium carbonate feed material, such as limestone, is first calcined to produce quicklime, and the quicklime is then soaked in w ater to yield calcium hydroxide or milk of lime.
  • the milk of lime is directly carbonated with carbon dioxide gas. This process has the advantage that no by-product is formed, and it is relatively easy to control the properties and purity of the calcium carbonate product.
  • the milk of lime is contacted with soda ash to produce, by double decomposition, a precipitate of calcium carbonate and a solution of sodium hydroxide.
  • the sodium hydroxide may be substantially completely separated from the calcium carbonate if this process is used commercially.
  • the milk of lime is first contacted with ammonium chloride to give a calcium chloride solution and ammonia gas.
  • the calcium chloride solution is then contacted with soda ash to produce by double decomposition precipitated calcium carbonate and a solution of sodium chloride.
  • the cry stals can be produced in a variety of different shapes and sizes, depending on the specific reaction process that is used.
  • the three main forms of PCC crystals are aragonite, rhombohedral, and scalenohedral, all of which are suitable for use in the herein disclosed nanocellulose, including mixtures thereof.
  • wet grinding of calcium carbonate involves the formation of an aqueous suspension of the calcium carbonate which may then be ground, optionally in the presence of a suitable dispersing agent.
  • a suitable dispersing agent for example, EP-A-614948 (the contents of which are incorporated by reference in their entirety ) for more information regarding the wet grinding of calcium carbonate.
  • the nanocellulose may include kaolin clay.
  • the kaolin clay may be a processed material derived from a natural source, namely raw natural kaolin clay mineral.
  • the processed kaolin clay may ty pically contain at least about 50% by weight kaolinite.
  • most commercially processed kaolin clays contain greater than about 75% by weight kaolinite and may contain greater than about 90%, in some cases greater than about 95% by weight of kaolinite.
  • the kaolin may be prepared from the raw natural kaolin clay mineral by one or more other processes which are well know n to those skilled in the art, for example by know n refining or beneficiation steps.
  • the clay mineral may be bleached with a reductive bleaching agent, such as sodium hydrosulfite. If sodium hydrosulfite is used, the bleached clay mineral may optionally be dewatered, and optionally w ashed and again optionally dewatered, after the sodium hydrosulfite bleaching step.
  • the clay mineral may be treated to remove impurities, for example, by flocculation, flotation, or magnetic separation techniques well known in the art.
  • the clay mineral may be untreated in the form of a solid or as an aqueous suspension.
  • the process for preparing the particulate kaolin clay may also include one or more comminution steps (e.g., grinding or milling).
  • the comminution may be carried out by use of beads or granules of a plastic (e.g. nylon), sand or ceramic grinding or milling aid.
  • the coarse kaolin may be refined to remove impurities and improve physical properties using well known procedures.
  • the kaolin clay may be treated by a known particle size classification procedure (e.g., screening and centrifuging (or both)), to obtain particles having a desired dso value or particle size distribution.
  • a known particle size classification procedure e.g., screening and centrifuging (or both)
  • the inorganic particulate material includes some extent of impurities.
  • the inorganic particulate material may contain less than about 5% by weight, preferably less than about 1% by weight, of other mineral impurities.
  • a nanocellulose-containing composition may comprise two or more of bentonite, GCC, PCC, and kaolin.
  • one or more other minerals may be included in the nanocellulose of the present disclosure.
  • Such one or more other minerals include, for example, kaolin, calcined kaolin, wollastonite, bauxite, talc, and mica.
  • the inorganic particulate material may have a particle size distribution in which at least about 10% by weight of the particles have an equivalent spherical diameter (e.s.d.) of less than 2 pm. for example, at least about 20% by weight, at least about 30% by weight, at least about 40% by weight, at least about 50% by weight, at least about 60% by weight, at least about 70% by weight, at least about 80% by weight, at least about 90% by weight, at least about 95% by weight, or about 100% of the particles have an e.s.d. of less than 2 pm.
  • Particle size properties, referred to herein for the inorganic particulate materials may be measured in a well-known manner.
  • the particle size properties of the inorganic particulate materials may be measured by sedimentation of the particulate material in a fully dispersed condition in an aqueous medium using a S edigraph 5100 machine as supplied by Micromeritics Instruments Corporation, Norcross, Ga., USA.
  • a S edigraph 5100 machine as supplied by Micromeritics Instruments Corporation, Norcross, Ga., USA.
  • Such a machine provides measurements and a plot of the cumulative percentage by weight of particles having a size, referred to in the art as the ‘'equivalent spherical diameter” (e.s.d), less than given e.s.d. values.
  • the mean particle size dso is the value determined in this way of the particle e.s.d. at which there are 50% by weight of the particles which have an equivalent spherical diameter less than that dso value.
  • the particle size properties referred to herein for the inorganic particulate materials are as measured by the w ell-known conventional method employed in the art of laser light scattering, using a Malvern Mastersizer 3000 or Malvern Insitec, as supplied by Malvern Instruments Ltd (or equivalent laser light scattering device or by other methods which give essentially the same result).
  • the size of particles in powders, suspensions and emulsions may be measured using the diffraction of a laser beam, based on an application of Mie theory.
  • Such a machine provides measurements and a plot of the cumulative percentage by volume of particles having a size, referred to in the art as the ‘equivalent spherical diameter’ (e.s.d), less than given e.s.d values.
  • the mean particle size d?o is the value determined in this way of the particle e.s.d at which there are 50% by volume of the particles which have an equivalent spherical diameter less than that dso value.
  • a nanocellulose-containing composition of the present disclosure may include one or more additives.
  • the nanocellulose-containing composition may include one or more emulsions, one or more fire retardants, and combinations thereof.
  • emulsion herein means a compound or composition configured to reduce water absorption of a paper or paperboard of w hich the emulsion is a component.
  • An emulsion may sometimes be referred to as a wax.
  • Example emulsions include, but are not limited to, polyvinyl acetate emulsion and paraffin emulsion.
  • a nanocellulose-containing composition of the present disclosure may include polyvinyl acetate emulsion and/or paraffin emulsion.
  • fire retardant herein means a compound or composition configured to provide fire retardant properties to a paper or paperboard of w hich the fire retardant is a component.
  • Example fire retardants include, but are not limited to, zinc oxide, aluminum hydroxide, and ammonium polyphosphate.
  • a nanocellulose-containing composition of the present disclosure may include zinc oxide, aluminum hydroxide, and/or ammonium polyphosphate.
  • a nanocellulose-containing composition of the present disclosure may include a solvent.
  • the solvent may be water, alcohol, toluene, or a combination thereof.
  • the alcohol may comprise one or more of ethanol, glycerol, and polyvinyl alcohol.
  • nanocellulose- containing composition may be applied to the same consolidating base sheet (an example of a paper or paperboard substrate) in a sequential manner.
  • a first nanocellulose-containing composition may have a first particle size distribution with a first mean size
  • a subsequently-applied second nanocellulose containing composition may have a second particle size distribution with a second mean size.
  • the first and second mean sizes may be different.
  • the first mean size (of the first particle size distribution) may be greater than the second mean size (of the second particle size distribution. Having the first mean size be greater than the second mean size may result in cheaper manufacturing of and a better draining paper or paper board as compared to one in which the first and second mean sizes are the same.
  • the first mean size (dso), of the first particle size distribution of the first nanocellulose-containing composition may be 5 pm, 10 pm, 15 pm, 20 pm, 25 pm, 30 pm, 35 pm. 40 pm. 45 pm. 50 pm. 55 pm. 60 pm. 65 pm. 70 pm. 75 pm. 80 pm. 85 pm. 90 pm.
  • the first mean size (dso), of the first particle size distribution of the first nanocellulose-containing composition may fall within a range of any of the foregoing-listing particle size distributions.
  • the first mean size (dso), of the first particle size distribution of the first nanocellulose-containing composition may be from 5 pm to 500 pm, or some other range therein.
  • the first particle size distribution, of the first nanocellulose- containing composition may have a steepness of 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, or any value there between (e.g., 20.1, 20,2, etc.).
  • the steepness, of the first particle size distribution of the first nanocellulose-containing composition may fall within a range of any of the foregoing-listed steepnesses.
  • the steepness, of the first particle size distribution of the first nanocellulose-containing composition may be from 20 to 50, or some other range therein.
  • the second mean size (dso), of the second particle size distribution of the second nanocellulose-containing composition may be 5 pm, 10 pm, 15 pm, 20 pm, 25 pm, 30 pm, 35 pm, 40 pm, 45 pm, 50 pm, 55 pm, 60 pm, 65 pm, 70 pm, 75 pm, 80 pm, 85 pm, 90 pm, 95 pm, 100 pm, 105 pm, 110 pm, 115 pm, 120 pm, 125 pm, 130 pm, 135 pm, 140 pm, 145 pm, 150 pm, 155 pm, 160 pm, 165 pm, 170 pm, 175 pm, 180 pm, 185 pm, 190 pm, 195 pm, 200 pm, 205 pm, 210 pm, 215 pm, 220 pm, 225 pm, 230 pm, 235 pm, 240 pm, 245 pm, 250 pm, 255 pm, 260 pm, 265 pm, 270 pm, 275 pm, 280 pm, 285 pm, 290 pm, 295 pm, 300 pm, 305 pm, 310 pm, 315 pm, 320 pm
  • the second mean size (dso), of the second particle size distribution of the second nanocellulose-containing composition may fall within a range of any of the foregoing-listing particle size distributions.
  • the second mean size (dso), of the second particle size distribution of the second nanocellulose- containing composition may be from 5 pm to 500 pm, or some other range therein.
  • the second particle size distribution, of the second nanocellulose-containing composition may have a steepness of 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, or any value there between (e.g., 20.1, 20,2, etc.).
  • the steepness, of the second particle size distribution of the second nanocellulose-containing composition may fall within a range of any of the foregoing-listed steepnesses.
  • the steepness, of the second particle size distribution of the second nanocellulose-containing composition may be from 20 to 50, or some other range therein.
  • the first mean size (of the first particle size distribution) may be less than the second mean size (of the second particle size distribution).
  • the first and second nanocellulose-containing compositions may comprise different nanocellulose.
  • the first and second nanocellulose-containing compositions may comprise different amounts of nanocellulose.
  • At least one nanocellulose-containing composition may include one or more inorganic particulate material, and at least one other nanocellulose-containing composition may be free of inorganic particulate material, or inorganic particulate material free.
  • the first nanocellulose-containing composition may include one or more inorganic particulate material, and the second nanocellulose-containing composition may be free of inorganic particulate material, or inorganic particulate material free.
  • Paperboard may be a single ply or multi-ply.
  • the present disclosure is directed to numerous forms of paperboard, including, by way of example and not limitation, boxboard or cartonboard, including folding cartons and rigid set-up boxes and folding boxboard; e.g. a liquid packaging board.
  • the paperboard may be chipboard or white lined chipboard.
  • the paperboard may be a Kraft board, laminated board.
  • the paperboard may be a solid bleached board or a solid unbleached board.
  • containerboard Various forms of containerboard are subsumed within the paperboard products of the present disclosure such as corrugated fibreboard (which is a building material and not a paper or paperboard product per se), linerboard or a binder’s board.
  • the paperboard described herein may be suitable for wrapping and packaging a variety of end-products, including for example foods.
  • the paperboard is or comprises linerboard.
  • the linerboard is or comprises one of brown Kraft liner, white top Kraft liner, test liner, white top test liner, brown light weight recycled liner, mottled test liner, and white top recycled liner.
  • the paper is or comprises Kraft paper.
  • the paper or paperboard substrate of the present disclosure has a grammage of from about 75 g/m 2 to about 400 g/m 2 , for example, from about 100 g/m 2 to about 375 g/m 2 , about 100 g/m 2 to about 350 g/m 2 , about 100 g/m 2 to about 300 g/m 2 , about 100 g/m 2 to about 275 g/m 2 , about 100 g/m 2 to about 250 g/m 2 , about 100 g/m 2 to about 225 g/m 2 , or from about 100 g/m 2 to about 200 g/m 2 .
  • the paper or paperboard substrate of the present disclosure comprises a base layer having a grammage ranging from about 25 g/m 2 to about 500 g/m 2 .
  • the resulting paper or paperboard may have a combination of desirable optical, surface, and mechanical properties, which are obtainable while utilizing relatively low amounts of a top ply having a high filler content, thereby offering light-weighting of the paper or paperboard compared to conventional top ply /substrate configurations.
  • Another benefit is that application of one or more nanocellulose- containing compositions in accordance with the present disclosure can result in a substantial reduction in the amount of fibre raw material required to produce the paper or paperboard. Further, any reduction in mechanical properties which may occur following application of a nanocellulose-containing composition may be offset by increasing the grammage of the paper or paperboard substrate, which is a relatively cheaper material, thereby recovering strength properties.
  • the paper or paperboard may comprise a further layer, or further layers, on the top layer of nanocellulose-containing composition.
  • a further layer or further layers, on the top layer of nanocellulose-containing composition.
  • one of, or at least one of, the further layers or plies is a barrier layer or ply, or wax layer or ply, or silicon layer or ply, or a combination of two or three of such layers.
  • a conventional white top liner typically has a white surface consisting of a white paper with relatively low filler content, typically in the 5-15% filler range. As a result, such white top liners tend to be quite rough and open with a coarse pore structure. This is not ideal for receiving printing ink.
  • the present disclosure also relates to methods for sequentially applying nanocellulose(s) onto the surface of paper or paperboard substrates.
  • a first method of the present disclosure relates to sequentially applying nanocellulose onto the surface of a paper and paperboard substrate, where the method comprises sequentially applying at least first and second layers of a (single) nanocellulose-containing composition to a consolidating base sheet after the consolidating base sheet leaves a headbox of a paper or paperboard machine, and where at least one of the first or second layers is applied via spraying.
  • both the first and second layers are applied via spraying.
  • the first layer is applied via curtain or slot coating, and the second layer is applied via spraying.
  • the method comprises applying the final (e.g., second, third, fourth, etc.) layer to cause the consolidating base sheet to have a heptane vapor transmission rate of about 0 g nT 2 day' 1 to about 100 g m' 2 day' 1 .
  • At least one of the first layer and the second layer is applied across substantially the entire width of the consolidating base sheet.
  • At least one of the first layer and the second layer is applied across the entire width of the consolidating base sheet.
  • the nanocellulose-containing composition comprises nanofibrillated cellulose, microfibrillated cellulose, or a combination thereof.
  • the nanocellulose-containing composition comprises microcrystalline cellulose, nanocry stalline cellulose, cellulose nanocrystals (CNCs), or a combination thereof.
  • the nanocellulose-containing composition comprises nanocellulose in a range of about 0.5 wt% to about 6 wt% based on the total weight of the nanocellulose-containing composition.
  • the nanocellulose-containing composition comprises nanocellulose in a range of about 1 wt% to about 2 wt% based on the total weight of the nanocellulose-containing composition.
  • the nanocellulose-containing composition comprises at least about 0.5 wt% nanocellulose based on the total weight of the nanocellulose-containing composition.
  • the nanocellulose-containing composition comprises at least about 1 wt% nanocellulose based on the total weight of the nanocellulose- containing composition.
  • the nanocellulose-containing composition comprises at least about 1.5 wt% nanocellulose based on the total weight of the nanocellulose-containing composition.
  • the nanocellulose-containing composition comprises at least about 2.5 wt% nanocellulose based on the total weight of the nanocellulose-containing composition.
  • the nanocellulose-containing composition comprises at most about 6 wt% nanocellulose based on the total weight of the nanocellulose- containing composition.
  • the nanocellulose-containing composition comprises at most about 3 wt% nanocellulose based on the total weight of the nanocellulose- containing composition.
  • the nanocellulose-containing composition comprises at most about 2 wt% nanocellulose based on the total weight of the nanocellulose- containing composition.
  • the nanocellulose-containing composition comprises one or more inorganic particulate material.
  • the one or more inorganic particulate material comprises bentonite, alkaline earth metal carbonate, alkaline earth metal sulphate, dolomite, gypsum, hydrous kandite clay, anhydrous calcined kandite clay, talc, mica, perlite, diatomaceous earth, magnesium hydroxide, aluminum trihydrate, or a combination thereof.
  • the one or more inorganic particulate material in bentonite.
  • the nanocellulose-containing composition comprises one or more starches.
  • the one or more starches comprise one or more cationic starches.
  • a cationic starch is a starch that is first '‘cooked” to dissolve the starch in water.
  • the nanocellulose-containing composition comprises one or more sizing agents.
  • the one or more sizing agents comprise rosin, rosin/aluminum emulsion, cationic rosin emulsion, alkylketene dimer, wax emulsion, succinic acid derivative, or a combination thereof.
  • the succinic acid derivative is alkenylsuccinic anhydride.
  • the nanocellulose-containing composition comprises one or more polyacrylamides. The one or more polyacrylamides may aid in drainage of the paper or paperboard.
  • the one or more polyacrylamides comprise poly diallyldimethylammonium chloride (polyDADMAC).
  • the nanocellulose-containing composition comprises one or more copolymers.
  • the one or more copolymers comprise ethylene vinyl alcohol (EV OH), polyvinyl alcohol (PVOH), or a combination thereof.
  • the one or more copolymers may be applied to a top of the last nanocellulose-containing layer applied to the consolidating base sheet.
  • a second method of the present disclosure relates to sequentially applying nanocellulose onto the surface of a paper or paperboard substrate, where the method comprises sequentially applying at least a first nanocellulose-containing composition and a second nanocellulose-containing composition to a consolidating base sheet after the consolidating base sheet leaves a headbox of a paper machine, and where at least one of the first nanocellulose-containing composition and the second nanocellulose containing composition is applied via spraying.
  • both the first nanocellulose-containing composition and the second nanocellulose containing composition are applied via spraying.
  • the first nanocellulose-containing composition is applied via curtain or slot coating, and the second nanocellulose-containing composition is applied via spraying.
  • the first nanocellulose-containing composition has a first particle size distribution
  • the second nanocellulose-containing composition has a second particle size distribution
  • the mean size, of the first particle size distribution is greater than the mean size of the second particle size distribution.
  • the mean size (dso), of the first particle size distribution of the first nanocellulose- containing composition may be 5 pm, 10 pm, 15 pm, 20 pm, 25 pm, 30 pm, 35 pm, 40 pm, 45 pm, 50 pm. 55 pm. 60 pm. 65 pm. 70 pm. 75 pm. 80 pm. 85 pm. 90 pm. 95 pm.
  • the mean size (dso), of the first particle size distribution of the first nanocellulose-containing composition may fall within a range of any of the foregoing-listing particle size distributions.
  • the mean size (dso), of the first particle size distribution of the first nanocellulose-containing composition may be from 5 pm to 500 pm, or some other range therein.
  • the first particle size distribution, of the first nanocellulose- containing composition may have a steepness of 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44. 45. 46, 47, 48, 49, 50, or any value there between (e.g., 20.1, 20,2, etc.).
  • the steepness, of the first particle size distribution of the first nanocellulose-containing composition may fall within a range of any of the foregoing-listed steepnesses.
  • the steepness, of the first particle size distribution of the first nanocellulose-containing composition may be from 20 to 50. or some other range therein.
  • the mean size (dso), of the second particle size distribution of the second nanocellulose-containing composition may be 5 pm, 10 pm, 15 pm, 20 pm, 25 pm, 30 pm, 35 gm, 40 gm, 45 gm, 50 gm, 55 gm, 60 gm, 65 gm, 70 gm, 75 gm, 80 gm, 85 gm, 90 gm, 95 gm, 100 gm, 105 gm, 110 gm, 115 gm, 120 gm, 125 pm, 130 gm, 135 gm, 140 gm, 145 gm, 150 gm. 155 gm, 160 gm, 165 gm.
  • the mean size (dso), of the second particle size distribution of the second nanocellulose-containing composition may fall within a range of any of the foregoing-listing particle size distributions.
  • the mean size (d.so), of the second particle size distribution of the second nanocellulose-containing composition may be from 5 pm to 500 gm, or some other range therein.
  • the second particle size distribution, of the second nanocellulose-containing composition may have a steepness of 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, or any value there between (e.g., 20.1, 20,2, etc.).
  • the steepness, of the second particle size distribution of the second nanocellulose-containing composition may fall within a range of any of the foregoing-listed steepnesses.
  • the steepness, of the second particle size distribution of the second nanocellulose-containing composition may be from 20 to 50, or some other range therein.
  • the second method comprises applying the final (e.g., second, third, fourth, etc.) nanocellulose-containing composition to cause the consolidating base sheet to have a heptane vapor transmission rate of about 0 g m" 2 day" 1 to about 100 g m" 2 day” 1 .
  • At least one of the first nanocellulose- containing composition and the second nanocellulose-containing composition is applied across substantially the entire width of the consolidating base sheet.
  • at least one of the first nanocellulose- containing composition and the second nanocellulose-containing composition is applied across the entire width of the consolidating base sheet.
  • the first nanocellulose-containing composition comprises nanofibrillated cellulose, microfibrillated cellulose, or a combination thereof.
  • the first nanocellulose-containing composition comprises microcrystalline cellulose, nanocrystalline cellulose, cellulose nanocrystals (CNCs), or a combination thereof.
  • the first nanocellulose-containing composition comprises first nanocellulose in a range of about 0.5 wt% to about 6 wt% based on the total weight of the first nanocellulose-containing composition.
  • the first nanocellulose-containing composition comprises first nanocellulose in a range of about 1 wt% to about 2 wt% based on the total weight of the first nanocellulose-containing composition.
  • the first nanocellulose-containing composition comprises at least about 0.5 wt% nanocellulose based on the total weight of the first nanocellulose-containing composition.
  • the first nanocellulose-containing composition comprises at least about 1 wt% first nanocellulose based on the total weight of the first nanocellulose-containing composition.
  • the first nanocellulose-containing composition comprises at least about 1.5 wt% first nanocellulose based on the total weight of the first nanocellulose-containing composition.
  • the first nanocellulose-containing composition comprises at least about 2.5 wt% first nanocellulose based on the total weight of the first nanocellulose-containing composition.
  • the first nanocellulose-containing composition comprises at most about 6 wt% first nanocellulose based on the total weight of the first nanocellulose-containing composition.
  • the first nanocellulose-containing composition comprises at most about 3wt% first nanocellulose based on the total weight of the first nanocellulose-containing composition.
  • the first nanocellulose-containing composition comprises at most about 2 wt% first nanocellulose based on the total weight of the first nanocellulose-containing composition.
  • the second nanocellulose-containing composition comprises nanofibrillated cellulose, microfibrillated cellulose, or a combination thereof.
  • the second nanocellulose-containing composition comprises microcrystalline cellulose, nanocrystalline cellulose, cellulose nanocrystals (CNCs), or a combination thereof.
  • the second nanocellulose-containing composition comprises second nanocellulose in a range of about 0.5 wt% to about 6 wt% based on the total weight of the second nanocellulose-containing composition.
  • the second nanocellulose-containing composition comprises second nanocellulose in a range of about 1 wt% to about 2 wt% based on the total weight of the second nanocellulose-containing composition.
  • the second nanocellulose-containing composition comprises at least about 0.5 wt% second nanocellulose based on the total weight of the second nanocellulose-containing composition.
  • the second nanocellulose-containing composition comprises at least about 1 wt% second nanocellulose based on the total weight of the second nanocellulose-containing composition.
  • the second nanocellulose-containing composition comprises at least about 1 .5 wt% second nanocellulose based on the total weight of the second nanocellulose-containing composition.
  • the second nanocellulose-containing composition comprises at least about 2.5 wt% second nanocellulose based on the total weight of the second nanocellulose-containing composition.
  • the second nanocellulose-containing composition comprises at most about 6 wt% second nanocellulose based on the total weight of the second nanocellulose-containing composition.
  • the second nanocellulose-containing composition comprises at most about 3 wt% second nanocellulose based on the total weight of the second nanocellulose-containing composition.
  • the second nanocellulose-containing composition comprises at most about 2 wt% second nanocellulose based on the total weight of the second nanocellulose-containing composition.
  • At least one of the first nanocellulose- containing composition and the second nanocellulose containing composition comprises one or more inorganic particulate material.
  • the first nanocellulose-containing composition may comprise one or more inorganic particulate material, but the second nanocellulose-containing composition may be free of inorganic particulate material.
  • the one or more inorganic particulate material comprises bentonite, alkaline earth metal carbonate, alkaline earth metal sulphate, dolomite, gypsum, hydrous kandite clay, anhydrous calcined kandite clay, talc, mica, perlite, diatomaceous earth, magnesium hydroxide, aluminum trihydrate, or a combination thereof.
  • the one or more inorganic particulate material is bentonite.
  • At least one of the first nanocellulose- containing composition and the second nanocellulose containing composition comprises one or more starches.
  • the one or more starches comprise one or more cationic starches.
  • At least one of the first nanocellulose- containing composition and the second nanocellulose containing composition comprises one or more sizing agents.
  • the one or more sizing agents comprise rosin, rosin/aluminum emulsion, cationic rosin emulsion, alkylketene dimer, wax emulsion, succinic acid derivative, or a combination thereof.
  • the succinic acid derivative is alkenylsuccinic anhydride.
  • at least one of the first nanocellulose- containing composition and the second nanocellulose containing composition comprises one or more polyacrylamides. The one or more polyacrylamides may aid in drainage of the paper or paperboard.
  • the one or more polyacrylamides comprise poly diallyldimethylammonium chloride (polyDADMAC).
  • At least one of the first nanocellulose- containing composition and the second nanocellulose containing composition comprises one or more copolymers.
  • the one or more copolymers comprise ethylene vinyl alcohol (EV OH), polyvinyl alcohol (PVOH), or a combination thereof.
  • the one or more copolymers may be applied to a top of the last nanocellulose-containing layer applied to the consolidating base sheet.
  • An aspect of the present disclosure relates to a method of manufacturing a multi-ply paper or paperboard product.
  • the method includes providing a consolidating base sheet of pulp following a headbox of a paper or paperboard machine, applying two or more layers of one or more nanocellulose-containing compositions onto the consolidating base sheet to form a consolidating multi-layer paper or paperboard structured material, and dewatering the multi-layer paper or paperboard structured material to produce the multi-ply paper or paperboard product.
  • a first layer of nanocellulose-containing composition is applied to the consolidating base sheet in an amount ranging from about 0. 1 g/m 2 to about 20 g/m 2 .
  • a second layer of nanocellulose-containing composition is applied to the consolidating base sheet in an amount ranging from about 1 g/m 2 to about 20 g/m 2 , and at least one of the first or second layers of nanocellulose-containing composition is applied by spraying.
  • Example pulps include, but are not limited to, recycled pulp, papermill broke, paper streams rich in mineral fillers, cellulosic materials from a papermill, chemical pulp, thermomechanical pulp, chemi-thermomechanical pulp, mechanical pulp, or a combination thereof.
  • the pulp comprises recycled paperboard.
  • the recycled paperboard is recycled corrugated containers.
  • the nanocellulose may include nanofibrillated cellulose, microfibrillated cellulose, or a combination thereof.
  • the nanocellulose may additionally or alternatively include microcrystalline cellulose, nanocrystallme cellulose, cellulose nanocrystals (CNCs), or a combination thereof.
  • the nanocellulose may be produced from hardwood pulp, softwood pulp, wheat straw pulp, bamboo, bagasse, virgin fiber, chemical pulp, chemithermomechanical pulp, mechanical pulp, thermomechanical pulp, kraft pulp, bleached long fibre kraft pulp, eucalyptus pulp, spruce pulp, pine pulp, beech pulp, hemp pulp, acacia cotton pulp, recycled pulp, papermill broke, paper steam rich in mineral fillers, or a combination thereof.
  • the hardwood pulp may be selected from the group consisting of eucalyptus, aspen, birch, and mixed hardwood pulps.
  • the hardwood pulp may include at least one of eucalyptus, aspen, birch, and mixed hardwood pulp.
  • the softwood pulp may be selected from the group consisting of spruce, pine, fir, larch, hemlock, and mixed softwood pulp.
  • the softwood pulp may include at least one of spruce, pine, fir, larch, hemlock, and mixed softwood pulp.
  • the method, of manufacturing a multi-ply paper or paperboard product may include applying one or more additional layers atop the two or more layers of one or more nanocellulose-containing compositions.
  • the one or more additional layers may include one or more of a barrier layer, a wax layer, and a silicon layer.
  • the method, of manufacturing a multi-ply paper or paperboard product may include applying an additional layer atop the two or more layers of one or more nanocellulose- containing compositions.
  • the additional layer may consist essentially of inorganic particulate material and nanocellulose.
  • the additional layer may consist essentially of inorganic particulate material and microfibrillated cellulose.
  • inorganic particulate material examples include calcium carbonate, ground calcium carbonate, precipitated calcium carbonate, magnesium carbonate, dolomite, gypsum, an anhydrous kandite clay, kaolin, perlite, bentonite, diatomaceous earth, wollastonite, talc, magnesium hydroxide, titanium dioxide, or aluminium trihydrate, or a combination thereof.
  • the inorganic particulate material comprises ground calcium carbonate and precipitated calcium carbonate.
  • the present disclosure also envisions a paper or paperboard manufacturing using the foregoing method.
  • the paper or paperboard may, in some embodiments, include a base layer having a grammage ranging from about 25 g/m 2 to about 500 g/m 2 .
  • the paper or paperboard may be a white top containerboard.
  • the present disclosure includes embodiments in which EVOH, PVOH, starch surface sizing agent, microcrystalline cellulose, and/or nanocry stalline cellulose may be applied at the size press of a paper machine.
  • the size press is part of the forming section of a paper machine.
  • the size press functions to increase consolidating base sheet solid consistency in order to ensure adequate drying capacity, to consolidate the sheet, and enable web runnability. Increased sheet consistency increases wet strength and improves sheet consolidation and fiber-to-fiber bonding.
  • the size press can also have a significant impact on quality parameters, such as smoothness, ink absorption, bulk, and moisture profile.
  • the size press utilizes one or more fabrics, interchangeably referred to as “press fabrics”’ or “press felts,” although it is noted that felt is a specific type of fabric that is made of individual fibers only (i.e., no yam in the fabric structure).
  • Typical consolidating base sheet consistency at the beginning of the size press section is about 20% solids and about 80% water, and at the end of the size press section is about 45% solids and about55% water.
  • the consolidating base sheet is transferred to a dryer section.
  • the consolidating base sheet having the one or more nanocellulose- containing compositions sequentially applied thereto, is compressed between one or two press fabrics and either two rolls, or a roll and a mated extended “shoe” in a press nip to squeeze water from inside the web and out of the felt fibers.
  • one or more layers of EVOH, PVOH, starch, surface sizing agent microcrystalline cellulose, and/or nanocrystalline cellulose may be applied to the surface of the consolidating base sheet.
  • One or more starches may be applied to the consolidating base sheet at the size press of the paper machine.
  • one or more cationic starches may be applied to the consolidating base sheet at the size press.
  • One or more surface sizing agents may be applied to the consolidating base sheet at the size press of the paper machine.
  • Example surface sizing agents include, but are not limited to rosin, rosin/aluminum emulsion, cationic rosin emulsion, alkylketene dimer, wax emulsion, and succinic acid derivative.
  • the surface sizing agent, applied at the size press may comprise rosin, rosin/aluminum emulsion, cationic rosin emulsion, alkylketene dimer, wax emulsion, succinic acid derivative, or a combination thereof.
  • the surface sizing agent, applied the size press may be selected from the group consisting of rosin, rosin/aluminum emulsion, cationic rosin emulsion, alkylketene dimer, wax emulsion, and succinic acid derivative.
  • the succinic acid derivative is alkenylsuccinic anhydride.
  • MFC surface application techniques based on curtain coating and spraying (up to 3 nozzles in sequence) were evaluated onto surfaces of bleached (80% UPM Eucalyptus, 20% St. Felecien softwood co-refined to 350 CSF) and unbleached (100% softwood Kraft 450 CSF) pulp furnishes.
  • bleached 80% UPM Eucalyptus, 20% St. Felecien softwood co-refined to 350 CSF
  • unbleached 100% softwood Kraft 450 CSF
  • Trial points 2-7 were prepared using the bleached pulp furnish and bleached pulp MFC.
  • Trial points 10 and 12-17 were prepared using unbleached pulp furnish and unbleached pulp MFC.
  • Trial points 18-21 were prepared using unbleached pulp furnish and unbleached pulp MFC that had been mixed with ground calcium carbonate (GCC) in a ratio of 1:1 (based on dry mass) to improve the visibility of the homogeneity/uniformity of coated surfaces.
  • GCC ground calcium carbonate
  • MFC applied by curtain surface application technique provided the greatest improvements to sheet properties (as indicated by low Bendtsen Porosity and HVTR, and high Gurley Porosity, Tensile Index and Burst Index values).
  • MFC A was made by a batch grinding process.
  • MFC B was made by a continuous grinding process. Both were ground with about 3,000 kWh/t.
  • MFC was applied as one or more surface layers to freshly -formed base sheets by filtration using the laboratory method described below.
  • An 80 g m" 2 base sheet made from a blend of 70/30 Eucalyptus/Pine bleached Kraft pulp refined to CSF 450 ml, was formed in a standard Messmer handsheet former (TAPPI T205) but not pressed or dried.
  • the base sheet was then turned upside down in order for its smoother side to be on top, and transferred to a second, vacuum-assisted handsheet former.
  • a specific amount of microfibrillated cellulose at a total solids content of 1.5% was measured out in order to achieve the desired grammage of the applied first layer on top of the base sheet. This was then diluted to a final volume of 400 ml with water.
  • a circle of diameter 7.46cm was cut from the sheet and placed over the cup with the MFC coated side facing downwards towards the heptane liquid. The cup was then sealed so that vapour could only escape by passing through the sheet.
  • the cup was re-weighed periodically over a 24 hr period.
  • the weight of the cup as a function of time was plotted and fitted to a simple linear function.
  • Table 4 shows the measured values of Gurley porosity' and heptane vapour transmission rate of samples coated with MFC as described above. Where one type of MFC only is used, it is clear that MFC B gives a higher value for Gurley porosity and a lower value for HVTR than MFC A. However, when two layers are used, equivalent performance to MFC B is obtained even when the lower layer of MFC A comprises 2/3 of the total. These data are represented graphically in Error! Reference source not found.and 8.
  • Example 3 Lab study on sequentially applied layers of UBSK based MFC
  • a Suzano wood free paper was used as the base sheet.
  • the base sheet was wetted and then the vacuum was applied to fix the wet sheet to the mesh.
  • MFC was diluted to 0.04% solids and applied by pouring into the sheet former and then applying the vacuum until no surface water was visible. If a second layer of MFC was applied, this occurred after there was no remaining surface water on the first layer and a wet network of MFC had formed. This was followed by drying in a Rapid Kothen drier for 7 minutes. The uncoated edges of the sheets were cut and disposed of. After coating, the sheets were left to equilibrate for a minimum of 15 hours at 23°C and 50% relative humidity.
  • Samples SU1 and SU3 are single layer coatings.
  • SU2 and SU4 are two-layer coatings using the same MFC in each layer.
  • SU5 is a two-layer coating where U1 is added first followed by U2 and SU5 is a two-layer coating where U2 is added first followed by U1 .
  • the barrier performance of the coatings was characterised using a Bendtsen porosity, Kit (grease resistance) and HVTR (heptane vapour transmission rate). The results are shown in Table 7 below .
  • Fig. 9A is a scanned image of a 4 gsm coating of coarser particle size MFC.
  • Fig. 9B is a scanned image of two separate and sequential coatings of 2 gsm each of coarser particle size MFC.
  • Fig. 9C is a scanned image of a 4 gsm coating of finer particle size MFC.
  • Fig. 9D is a scanned image of two separate and sequential coatings of 2 gsm each of finer particle size MFC.
  • Fig. 9E is a scanned image of two separate and sequential coatings of 2 gsm each of coarser particle size MFC followed by a 2 gsm coating of finer particle size MFC.
  • Fig. 9F is a scanned image of two separate and sequential coatings of 2 gsm each of finer particle size MFC followed by a 2 gsm coating of a coarser particle size MFC.
  • Example 4 Lab study on sequentially applied layers of Eucalyptus based MFC [0465] Two samples of MFC were produced using Eucalyptus pulp and by grinding with a wet stirred media mill. Sample El is less processed and has a coarser particle size with the same fibre length (Lc(l)) but lower Fines A, significantly lower Fines B and lower Fines content than E2.
  • a Suzano wood free paper was used as the base sheet.
  • the base sheet was wetted and then the vacuum was applied to fix the wet sheet to the mesh.
  • MFC was diluted to 0.04% solids and applied by pouring into the sheet former and then applying the vacuum until no surface water was visible. If a second layer of MFC was applied, this occurred after there was no remaining surface water on the first layer and a wet netw ork of MFC had formed. This was followed by drying in a Rapid Kothen drier for 7 minutes. The uncoated edges of the sheets w ere cut and disposed of. After coating, the sheets were left to equilibrate for a minimum of 15 hours at 23°C and 50% relative humidity.
  • Samples SI and S3 are single layer coatings.
  • S2 and S4 are two-layer coatings using the same MFC in each layer.
  • S5 is a two-layer coating where E2 is added first followed by El and S5 is a two-layer coating where El is added first follow ed by E2. 9 ⁇ Samples and coatins weights
  • the barrier performance of the coatings was characterised using a Bendtsen porosity, Kit (grease resistance) and HVTR (heptane vapour transmission rate). The results are show n in Table 10 below. HVTR was performed at 22°C and 52% RH.
  • HVTR was performed at 22°C and 52% RH.
  • HVTR is improved when two layers of MFC are coated compared to one layer of the same total coat weight and sample, for example sample S2 has a lower HVTR than sample SI.
  • the most effective heptane vapour barriers were a double layer coating of E2 (sample S4) or a coating of El followed by E2 (sample S6).
  • Fig. 10A is an SEM image depicting a 4 gsm surface coating of coarser particle size eucalyptus MFC composition coated onto a base paper.
  • Fig. 10B depicts a cross section of a coating of coarser particle size eucalyptus MFC composition coated onto a base paper.
  • Fig. 1 1 A is an SEM image depicting a 4 gsm surface coating of finer particle size eucalyptus MFC composition coated onto a base paper.
  • Fig. 11B depicts a cross section of a coating of finer particle size eucalyptus MFC composition coated onto a base paper.
  • Fig. 12A is an SEM image depicting a 2 gsm coating of high Fines B eucalyptus MFC composition coated onto a base paper followed by a coating of 2 gsm of low Fines B eucalyptus MFC composition.
  • Fig. 12B is an SEM image depicting a cross section of a 2 gsm coating of high Fines B eucalyptus MFC composition coated onto a base paper followed by a coating of 2 gsm of low Fines B eucalyptus MFC composition.
  • Fig. 13A is an SEM image depicting a 2 gsm coating of a low Fines B eucalyptus MFC composition coated onto a base paper followed by a 2 gsm coating of a high Fines B eucalyptus MFC composition.
  • Fig. 13B is an SEM image depicting a cross section of a 2 gsm coating of a low Fines B eucalyptus MFC composition coated onto a base paper followed by a 2 gsm coating of a high Fines B eucalyptus MFC composition.
  • this sample could be taken and coated by drawdown, but the coated sample size would be small because it’s already starting from a much smaller area (Step 4, Fig. 9).
  • a pritt stick glue was used to completely coat the reverse of the foil with glue and then stick the sample to the foil, barrier side up (i.e. barrier does not make contact with the glue/foil).
  • the cell settings were: temperature: 23°C, test gas RH: 50%, carrier gas RH: 5%, and permeant concentration: 100%.
  • the terms “comprising” (and any form of comprising, such as “comprise”, “comprises”, and “comprised”), “having” (and any form of having, such as “have” and “has”), “including” (and any form of including, such as “includes” and “include”), or “containing” (and any form of containing, such as “contains” and “contain”), are inclusive or open-ended and do not exclude additional, unrecited elements or method steps.
  • dry weight is intended to mean the weight of the composition free of liquid, in particular free of water.
  • dry weight is intended to mean the weight of the composition free of liquid, in particular free of water.
  • the term “include” and its grammatical variants are intended to be non-limiting, such that recitation of items in a list is not to the exclusion of other like items that can be substituted or added to the listed items.
  • integer from X to Y means any integer that includes the endpoints.
  • integer from 1 to 5" means 1, 2, 3, 4, or 5.
  • recycled cellulose-containing materials means recycled pulp or a papermill broke and/or industrial waste, or paper streams rich in mineral fillers and cellulosic materials from a papermill.

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Abstract

L'invention concerne des procédés et des systèmes pour appliquer des revêtements barrières sur du papier et du carton revêtus de nanocellulose.
PCT/IB2023/000723 2022-11-22 2023-11-20 Revêtements barrières appliqués sur du papier et du carton revêtus de nanocellulose WO2024110786A1 (fr)

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